view src/window.c @ 33471:baa62f464436 v9.0.1988

patch 9.0.1988: Vim9: potential use-after-free for class members Commit: https://github.com/vim/vim/commit/d2f4800099733216e28d59e1a5710f624b0d9ec1 Author: Yegappan Lakshmanan <yegappan@yahoo.com> Date: Thu Oct 5 20:24:18 2023 +0200 patch 9.0.1988: Vim9: potential use-after-free for class members Problem: Vim9: potential use-after-free for class members Solution: Use the class-related grow array for storing the member type instead of using a temporary type list grow array Use the type list grow array associated with the class than using a temporary type list grow array to allocate the class member type. For simple types, a predefined type is used. For complex types, the type is dynamically allocated from a grow array. For class variables, the type grow array in the class should be used. So that the lifetime of the type is same as the lifetime of the class. closes: #13279 Signed-off-by: Christian Brabandt <cb@256bit.org> Co-authored-by: Yegappan Lakshmanan <yegappan@yahoo.com>
author Christian Brabandt <cb@256bit.org>
date Thu, 05 Oct 2023 20:30:11 +0200
parents 201c54cdde82
children 7624df087ebf
line wrap: on
line source

/* vi:set ts=8 sts=4 sw=4 noet:
 *
 * VIM - Vi IMproved	by Bram Moolenaar
 *
 * Do ":help uganda"  in Vim to read a list of people who contributed.
 * Do ":help credits" in Vim to see a list of people who contributed.
 * See README.txt for an overview of the Vim source code.
 */

#include "vim.h"

static void cmd_with_count(char *cmd, char_u *bufp, size_t bufsize, long Prenum);
static void win_init(win_T *newp, win_T *oldp, int flags);
static void win_init_some(win_T *newp, win_T *oldp);
static void frame_comp_pos(frame_T *topfrp, int *row, int *col);
static void frame_setheight(frame_T *curfrp, int height);
static void frame_setwidth(frame_T *curfrp, int width);
static void win_exchange(long);
static void win_rotate(int, int);
static void win_totop(int size, int flags);
static void win_equal_rec(win_T *next_curwin, int current, frame_T *topfr, int dir, int col, int row, int width, int height);
static void trigger_winclosed(win_T *win);
static win_T *win_free_mem(win_T *win, int *dirp, tabpage_T *tp);
static frame_T *win_altframe(win_T *win, tabpage_T *tp);
static tabpage_T *alt_tabpage(void);
static win_T *frame2win(frame_T *frp);
static int frame_has_win(frame_T *frp, win_T *wp);
static void win_fix_scroll(int resize);
static void win_fix_cursor(int normal);
static void frame_new_height(frame_T *topfrp, int height, int topfirst, int wfh);
static int frame_fixed_height(frame_T *frp);
static int frame_fixed_width(frame_T *frp);
static void frame_add_statusline(frame_T *frp);
static void frame_new_width(frame_T *topfrp, int width, int leftfirst, int wfw);
static void frame_add_vsep(frame_T *frp);
static int frame_minwidth(frame_T *topfrp, win_T *next_curwin);
static void frame_fix_width(win_T *wp);
static int win_alloc_firstwin(win_T *oldwin);
static void new_frame(win_T *wp);
static tabpage_T *alloc_tabpage(void);
static int leave_tabpage(buf_T *new_curbuf, int trigger_leave_autocmds);
static void enter_tabpage(tabpage_T *tp, buf_T *old_curbuf, int trigger_enter_autocmds, int trigger_leave_autocmds);
static void frame_fix_height(win_T *wp);
static int frame_minheight(frame_T *topfrp, win_T *next_curwin);
static int may_open_tabpage(void);
static int win_enter_ext(win_T *wp, int flags);
static void win_free(win_T *wp, tabpage_T *tp);
static void win_append(win_T *after, win_T *wp);
static void frame_append(frame_T *after, frame_T *frp);
static void frame_insert(frame_T *before, frame_T *frp);
static void frame_remove(frame_T *frp);
static void win_goto_ver(int up, long count);
static void win_goto_hor(int left, long count);
static void frame_add_height(frame_T *frp, int n);
static void last_status_rec(frame_T *fr, int statusline);

static void make_snapshot_rec(frame_T *fr, frame_T **frp);
static void clear_snapshot(tabpage_T *tp, int idx);
static void clear_snapshot_rec(frame_T *fr);
static int check_snapshot_rec(frame_T *sn, frame_T *fr);
static win_T *restore_snapshot_rec(frame_T *sn, frame_T *fr);
static win_T *get_snapshot_curwin(int idx);

static int frame_check_height(frame_T *topfrp, int height);
static int frame_check_width(frame_T *topfrp, int width);

static win_T *win_alloc(win_T *after, int hidden);

#define NOWIN		((win_T *)-1)	// non-existing window

#define ROWS_AVAIL (Rows - p_ch - tabline_height())

// flags for win_enter_ext()
#define WEE_UNDO_SYNC			0x01
#define WEE_CURWIN_INVALID		0x02
#define WEE_TRIGGER_NEW_AUTOCMDS	0x04
#define WEE_TRIGGER_ENTER_AUTOCMDS	0x08
#define WEE_TRIGGER_LEAVE_AUTOCMDS	0x10
#define WEE_ALLOW_PARSE_MESSAGES	0x20

static char *m_onlyone = N_("Already only one window");

// When non-zero splitting a window is forbidden.  Used to avoid that nasty
// autocommands mess up the window structure.
static int split_disallowed = 0;

// When non-zero closing a window is forbidden.  Used to avoid that nasty
// autocommands mess up the window structure.
static int close_disallowed = 0;

/*
 * Disallow changing the window layout (split window, close window, move
 * window).  Resizing is still allowed.
 * Used for autocommands that temporarily use another window and need to
 * make sure the previously selected window is still there.
 * Must be matched with exactly one call to window_layout_unlock()!
 */
    static void
window_layout_lock(void)
{
    ++split_disallowed;
    ++close_disallowed;
}

    static void
window_layout_unlock(void)
{
    --split_disallowed;
    --close_disallowed;
}

/*
 * When the window layout cannot be changed give an error and return TRUE.
 * "cmd" indicates the action being performed and is used to pick the relevant
 * error message.
 */
    int
window_layout_locked(enum CMD_index cmd)
{
    if (split_disallowed > 0 || close_disallowed > 0)
    {
	if (close_disallowed == 0 && cmd == CMD_tabnew)
	    emsg(_(e_cannot_split_window_when_closing_buffer));
	else
	    emsg(_(e_not_allowed_to_change_window_layout_in_this_autocmd));
	return TRUE;
    }
    return FALSE;
}

// #define WIN_DEBUG
#ifdef WIN_DEBUG
/*
 * Call this method to log the current window layout.
 */
    static void
log_frame_layout(frame_T *frame)
{
    ch_log(NULL, "layout %s, wi: %d, he: %d, wwi: %d, whe: %d, id: %d",
	    frame->fr_layout == FR_LEAF ? "LEAF"
				  : frame->fr_layout == FR_ROW ? "ROW" : "COL",
	    frame->fr_width,
	    frame->fr_height,
	    frame->fr_win == NULL ? -1 : frame->fr_win->w_width,
	    frame->fr_win == NULL ? -1 : frame->fr_win->w_height,
	    frame->fr_win == NULL ? -1 : frame->fr_win->w_id);
    if (frame->fr_child != NULL)
    {
	ch_log(NULL, "children");
	log_frame_layout(frame->fr_child);
	if (frame->fr_next != NULL)
	    ch_log(NULL, "END of children");
    }
    if (frame->fr_next != NULL)
	log_frame_layout(frame->fr_next);
}
#endif

/*
 * Return the current window, unless in the cmdline window and "prevwin" is
 * set, then return "prevwin".
 */
    win_T *
prevwin_curwin(void)
{
    // In cmdwin, the alternative buffer should be used.
    return is_in_cmdwin() && prevwin != NULL ? prevwin : curwin;
}

/*
 * If the 'switchbuf' option contains "useopen" or "usetab", then try to jump
 * to a window containing "buf".
 * Returns the pointer to the window that was jumped to or NULL.
 */
    win_T *
swbuf_goto_win_with_buf(buf_T *buf)
{
    win_T   *wp = NULL;

    if (buf == NULL)
	return wp;

    // If 'switchbuf' contains "useopen": jump to first window in the current
    // tab page containing "buf" if one exists.
    if (swb_flags & SWB_USEOPEN)
	wp = buf_jump_open_win(buf);

    // If 'switchbuf' contains "usetab": jump to first window in any tab page
    // containing "buf" if one exists.
    if (wp == NULL && (swb_flags & SWB_USETAB))
	wp = buf_jump_open_tab(buf);

    return wp;
}

/*
 * All CTRL-W window commands are handled here, called from normal_cmd().
 */
    void
do_window(
    int		nchar,
    long	Prenum,
    int		xchar)	    // extra char from ":wincmd gx" or NUL
{
    long	Prenum1;
    win_T	*wp;
    char_u	*ptr;
    linenr_T    lnum = -1;
#ifdef FEAT_FIND_ID
    int		type = FIND_DEFINE;
    int		len;
#endif
    char_u	cbuf[40];

    if (ERROR_IF_ANY_POPUP_WINDOW)
	return;

#define CHECK_CMDWIN \
    do { \
	if (cmdwin_type != 0) \
	{ \
	    emsg(_(e_invalid_in_cmdline_window)); \
	    return; \
	} \
    } while (0)

    Prenum1 = Prenum == 0 ? 1 : Prenum;

    switch (nchar)
    {
// split current window in two parts, horizontally
    case 'S':
    case Ctrl_S:
    case 's':
		CHECK_CMDWIN;
		reset_VIsual_and_resel();	// stop Visual mode
		// When splitting the quickfix window open a new buffer in it,
		// don't replicate the quickfix buffer.
		if (bt_quickfix(curbuf))
		    goto newwindow;
#ifdef FEAT_GUI
		need_mouse_correct = TRUE;
#endif
		(void)win_split((int)Prenum, 0);
		break;

// split current window in two parts, vertically
    case Ctrl_V:
    case 'v':
		CHECK_CMDWIN;
		reset_VIsual_and_resel();	// stop Visual mode
		// When splitting the quickfix window open a new buffer in it,
		// don't replicate the quickfix buffer.
		if (bt_quickfix(curbuf))
		    goto newwindow;
#ifdef FEAT_GUI
		need_mouse_correct = TRUE;
#endif
		(void)win_split((int)Prenum, WSP_VERT);
		break;

// split current window and edit alternate file
    case Ctrl_HAT:
    case '^':
		CHECK_CMDWIN;
		reset_VIsual_and_resel();	// stop Visual mode

		if (buflist_findnr(Prenum == 0
					? curwin->w_alt_fnum : Prenum) == NULL)
		{
		    if (Prenum == 0)
			emsg(_(e_no_alternate_file));
		    else
			semsg(_(e_buffer_nr_not_found), Prenum);
		    break;
		}

		if (!curbuf_locked() && win_split(0, 0) == OK)
		    (void)buflist_getfile(
			    Prenum == 0 ? curwin->w_alt_fnum : Prenum,
			    (linenr_T)0, GETF_ALT, FALSE);
		break;

// open new window
    case Ctrl_N:
    case 'n':
		CHECK_CMDWIN;
		reset_VIsual_and_resel();	// stop Visual mode
newwindow:
		if (Prenum)
		    // window height
		    vim_snprintf((char *)cbuf, sizeof(cbuf) - 5, "%ld", Prenum);
		else
		    cbuf[0] = NUL;
#if defined(FEAT_QUICKFIX)
		if (nchar == 'v' || nchar == Ctrl_V)
		    STRCAT(cbuf, "v");
#endif
		STRCAT(cbuf, "new");
		do_cmdline_cmd(cbuf);
		break;

// quit current window
    case Ctrl_Q:
    case 'q':
		reset_VIsual_and_resel();	// stop Visual mode
		cmd_with_count("quit", cbuf, sizeof(cbuf), Prenum);
		do_cmdline_cmd(cbuf);
		break;

// close current window
    case Ctrl_C:
    case 'c':
		reset_VIsual_and_resel();	// stop Visual mode
		cmd_with_count("close", cbuf, sizeof(cbuf), Prenum);
		do_cmdline_cmd(cbuf);
		break;

#if defined(FEAT_QUICKFIX)
// close preview window
    case Ctrl_Z:
    case 'z':
		CHECK_CMDWIN;
		reset_VIsual_and_resel();	// stop Visual mode
		do_cmdline_cmd((char_u *)"pclose");
		break;

// cursor to preview window
    case 'P':
		FOR_ALL_WINDOWS(wp)
		    if (wp->w_p_pvw)
			break;
		if (wp == NULL)
		    emsg(_(e_there_is_no_preview_window));
		else
		    win_goto(wp);
		break;
#endif

// close all but current window
    case Ctrl_O:
    case 'o':
		CHECK_CMDWIN;
		reset_VIsual_and_resel();	// stop Visual mode
		cmd_with_count("only", cbuf, sizeof(cbuf), Prenum);
		do_cmdline_cmd(cbuf);
		break;

// cursor to next window with wrap around
    case Ctrl_W:
    case 'w':
// cursor to previous window with wrap around
    case 'W':
		CHECK_CMDWIN;
		if (ONE_WINDOW && Prenum != 1)	// just one window
		    beep_flush();
		else
		{
		    if (Prenum)			// go to specified window
		    {
			for (wp = firstwin; --Prenum > 0; )
			{
			    if (wp->w_next == NULL)
				break;
			    else
				wp = wp->w_next;
			}
		    }
		    else
		    {
			if (nchar == 'W')	    // go to previous window
			{
			    wp = curwin->w_prev;
			    if (wp == NULL)
				wp = lastwin;	    // wrap around
			}
			else			    // go to next window
			{
			    wp = curwin->w_next;
			    if (wp == NULL)
				wp = firstwin;	    // wrap around
			}
		    }
		    win_goto(wp);
		}
		break;

// cursor to window below
    case 'j':
    case K_DOWN:
    case Ctrl_J:
		CHECK_CMDWIN;
		win_goto_ver(FALSE, Prenum1);
		break;

// cursor to window above
    case 'k':
    case K_UP:
    case Ctrl_K:
		CHECK_CMDWIN;
		win_goto_ver(TRUE, Prenum1);
		break;

// cursor to left window
    case 'h':
    case K_LEFT:
    case Ctrl_H:
    case K_BS:
		CHECK_CMDWIN;
		win_goto_hor(TRUE, Prenum1);
		break;

// cursor to right window
    case 'l':
    case K_RIGHT:
    case Ctrl_L:
		CHECK_CMDWIN;
		win_goto_hor(FALSE, Prenum1);
		break;

// move window to new tab page
    case 'T':
		CHECK_CMDWIN;
		if (one_window())
		    msg(_(m_onlyone));
		else
		{
		    tabpage_T	*oldtab = curtab;
		    tabpage_T	*newtab;

		    // First create a new tab with the window, then go back to
		    // the old tab and close the window there.
		    wp = curwin;
		    if (win_new_tabpage((int)Prenum) == OK
						     && valid_tabpage(oldtab))
		    {
			newtab = curtab;
			goto_tabpage_tp(oldtab, TRUE, TRUE);
			if (curwin == wp)
			    win_close(curwin, FALSE);
			if (valid_tabpage(newtab))
			    goto_tabpage_tp(newtab, TRUE, TRUE);
		    }
		}
		break;

// cursor to top-left window
    case 't':
    case Ctrl_T:
		win_goto(firstwin);
		break;

// cursor to bottom-right window
    case 'b':
    case Ctrl_B:
		win_goto(lastwin);
		break;

// cursor to last accessed (previous) window
    case 'p':
    case Ctrl_P:
		if (!win_valid(prevwin))
		    beep_flush();
		else
		    win_goto(prevwin);
		break;

// exchange current and next window
    case 'x':
    case Ctrl_X:
		CHECK_CMDWIN;
		win_exchange(Prenum);
		break;

// rotate windows downwards
    case Ctrl_R:
    case 'r':
		CHECK_CMDWIN;
		reset_VIsual_and_resel();	// stop Visual mode
		win_rotate(FALSE, (int)Prenum1);    // downwards
		break;

// rotate windows upwards
    case 'R':
		CHECK_CMDWIN;
		reset_VIsual_and_resel();	// stop Visual mode
		win_rotate(TRUE, (int)Prenum1);	    // upwards
		break;

// move window to the very top/bottom/left/right
    case 'K':
    case 'J':
    case 'H':
    case 'L':
		CHECK_CMDWIN;
		win_totop((int)Prenum,
			((nchar == 'H' || nchar == 'L') ? WSP_VERT : 0)
			| ((nchar == 'H' || nchar == 'K') ? WSP_TOP : WSP_BOT));
		break;

// make all windows the same width and/or height
    case '=':
		{
		    int mod = cmdmod.cmod_split & (WSP_VERT | WSP_HOR);
#ifdef FEAT_GUI
		    need_mouse_correct = TRUE;
#endif
		    win_equal(NULL, FALSE,
			   mod == WSP_VERT ? 'v' : mod == WSP_HOR ? 'h' : 'b');
		}
		break;

// increase current window height
    case '+':
#ifdef FEAT_GUI
		need_mouse_correct = TRUE;
#endif
		win_setheight(curwin->w_height + (int)Prenum1);
		break;

// decrease current window height
    case '-':
#ifdef FEAT_GUI
		need_mouse_correct = TRUE;
#endif
		win_setheight(curwin->w_height - (int)Prenum1);
		break;

// set current window height
    case Ctrl__:
    case '_':
#ifdef FEAT_GUI
		need_mouse_correct = TRUE;
#endif
		win_setheight(Prenum ? (int)Prenum : 9999);
		break;

// increase current window width
    case '>':
#ifdef FEAT_GUI
		need_mouse_correct = TRUE;
#endif
		win_setwidth(curwin->w_width + (int)Prenum1);
		break;

// decrease current window width
    case '<':
#ifdef FEAT_GUI
		need_mouse_correct = TRUE;
#endif
		win_setwidth(curwin->w_width - (int)Prenum1);
		break;

// set current window width
    case '|':
#ifdef FEAT_GUI
		need_mouse_correct = TRUE;
#endif
		win_setwidth(Prenum != 0 ? (int)Prenum : 9999);
		break;

// jump to tag and split window if tag exists (in preview window)
#if defined(FEAT_QUICKFIX)
    case '}':
		CHECK_CMDWIN;
		if (Prenum)
		    g_do_tagpreview = Prenum;
		else
		    g_do_tagpreview = p_pvh;
#endif
		// FALLTHROUGH
    case ']':
    case Ctrl_RSB:
		CHECK_CMDWIN;
		// keep Visual mode, can select words to use as a tag
		if (Prenum)
		    postponed_split = Prenum;
		else
		    postponed_split = -1;
#ifdef FEAT_QUICKFIX
		if (nchar != '}')
		    g_do_tagpreview = 0;
#endif

		// Execute the command right here, required when "wincmd ]"
		// was used in a function.
		do_nv_ident(Ctrl_RSB, NUL);
		postponed_split = 0;
		break;

// edit file name under cursor in a new window
    case 'f':
    case 'F':
    case Ctrl_F:
wingotofile:
		CHECK_CMDWIN;
		if (check_text_or_curbuf_locked(NULL))
		    break;

		ptr = grab_file_name(Prenum1, &lnum);
		if (ptr != NULL)
		{
		    tabpage_T	*oldtab = curtab;
		    win_T	*oldwin = curwin;
#ifdef FEAT_GUI
		    need_mouse_correct = TRUE;
#endif
		    setpcmark();

		    // If 'switchbuf' is set to 'useopen' or 'usetab' and the
		    // file is already opened in a window, then jump to it.
		    wp = NULL;
		    if ((swb_flags & (SWB_USEOPEN | SWB_USETAB))
						&& cmdmod.cmod_tab == 0)
			wp = swbuf_goto_win_with_buf(buflist_findname_exp(ptr));

		    if (wp == NULL && win_split(0, 0) == OK)
		    {
			RESET_BINDING(curwin);
			if (do_ecmd(0, ptr, NULL, NULL, ECMD_LASTL,
						   ECMD_HIDE, NULL) == FAIL)
			{
			    // Failed to open the file, close the window
			    // opened for it.
			    win_close(curwin, FALSE);
			    goto_tabpage_win(oldtab, oldwin);
			}
			else
			    wp = curwin;
		    }

		    if (wp != NULL && nchar == 'F' && lnum >= 0)
		    {
			curwin->w_cursor.lnum = lnum;
			check_cursor_lnum();
			beginline(BL_SOL | BL_FIX);
		    }
		    vim_free(ptr);
		}
		break;

#ifdef FEAT_FIND_ID
// Go to the first occurrence of the identifier under cursor along path in a
// new window -- webb
    case 'i':			    // Go to any match
    case Ctrl_I:
		type = FIND_ANY;
		// FALLTHROUGH
    case 'd':			    // Go to definition, using 'define'
    case Ctrl_D:
		CHECK_CMDWIN;
		if ((len = find_ident_under_cursor(&ptr, FIND_IDENT)) == 0)
		    break;

		// Make a copy, if the line was changed it will be freed.
		ptr = vim_strnsave(ptr, len);
		if (ptr == NULL)
		    break;

		find_pattern_in_path(ptr, 0, len, TRUE,
			Prenum == 0 ? TRUE : FALSE, type,
			Prenum1, ACTION_SPLIT, (linenr_T)1, (linenr_T)MAXLNUM);
		vim_free(ptr);
		curwin->w_set_curswant = TRUE;
		break;
#endif

// Quickfix window only: view the result under the cursor in a new split.
#if defined(FEAT_QUICKFIX)
    case K_KENTER:
    case CAR:
		if (bt_quickfix(curbuf))
		    qf_view_result(TRUE);
		break;
#endif

// CTRL-W g  extended commands
    case 'g':
    case Ctrl_G:
		CHECK_CMDWIN;
#ifdef USE_ON_FLY_SCROLL
		dont_scroll = TRUE;		// disallow scrolling here
#endif
		++no_mapping;
		++allow_keys;   // no mapping for xchar, but allow key codes
		if (xchar == NUL)
		    xchar = plain_vgetc();
		LANGMAP_ADJUST(xchar, TRUE);
		--no_mapping;
		--allow_keys;
		(void)add_to_showcmd(xchar);

		switch (xchar)
		{
#if defined(FEAT_QUICKFIX)
		    case '}':
			xchar = Ctrl_RSB;
			if (Prenum)
			    g_do_tagpreview = Prenum;
			else
			    g_do_tagpreview = p_pvh;
#endif
			// FALLTHROUGH
		    case ']':
		    case Ctrl_RSB:
			// keep Visual mode, can select words to use as a tag
			if (Prenum)
			    postponed_split = Prenum;
			else
			    postponed_split = -1;

			// Execute the command right here, required when
			// "wincmd g}" was used in a function.
			do_nv_ident('g', xchar);
			postponed_split = 0;
			break;

		    case 'f':	    // CTRL-W gf: "gf" in a new tab page
		    case 'F':	    // CTRL-W gF: "gF" in a new tab page
			cmdmod.cmod_tab = tabpage_index(curtab) + 1;
			nchar = xchar;
			goto wingotofile;

		    case 't':	    // CTRL-W gt: go to next tab page
			goto_tabpage((int)Prenum);
			break;

		    case 'T':	    // CTRL-W gT: go to previous tab page
			goto_tabpage(-(int)Prenum1);
			break;

		    case TAB:	    // CTRL-W g<Tab>: go to last used tab page
			if (goto_tabpage_lastused() == FAIL)
			    beep_flush();
			break;

		    default:
			beep_flush();
			break;
		}
		break;

    default:	beep_flush();
		break;
    }
}

/*
 * Figure out the address type for ":wincmd".
 */
    void
get_wincmd_addr_type(char_u *arg, exarg_T *eap)
{
    switch (*arg)
    {
    case 'S':
    case Ctrl_S:
    case 's':
    case Ctrl_N:
    case 'n':
    case 'j':
    case Ctrl_J:
    case 'k':
    case Ctrl_K:
    case 'T':
    case Ctrl_R:
    case 'r':
    case 'R':
    case 'K':
    case 'J':
    case '+':
    case '-':
    case Ctrl__:
    case '_':
    case '|':
    case ']':
    case Ctrl_RSB:
    case 'g':
    case Ctrl_G:
    case Ctrl_V:
    case 'v':
    case 'h':
    case Ctrl_H:
    case 'l':
    case Ctrl_L:
    case 'H':
    case 'L':
    case '>':
    case '<':
#if defined(FEAT_QUICKFIX)
    case '}':
#endif
    case 'f':
    case 'F':
    case Ctrl_F:
#ifdef FEAT_FIND_ID
    case 'i':
    case Ctrl_I:
    case 'd':
    case Ctrl_D:
#endif
		// window size or any count
		eap->addr_type = ADDR_OTHER;
		break;

    case Ctrl_HAT:
    case '^':
		// buffer number
		eap->addr_type = ADDR_BUFFERS;
		break;

    case Ctrl_Q:
    case 'q':
    case Ctrl_C:
    case 'c':
    case Ctrl_O:
    case 'o':
    case Ctrl_W:
    case 'w':
    case 'W':
    case 'x':
    case Ctrl_X:
		// window number
		eap->addr_type = ADDR_WINDOWS;
		break;

#if defined(FEAT_QUICKFIX)
    case Ctrl_Z:
    case 'z':
    case 'P':
#endif
    case 't':
    case Ctrl_T:
    case 'b':
    case Ctrl_B:
    case 'p':
    case Ctrl_P:
    case '=':
    case CAR:
		// no count
		eap->addr_type = ADDR_NONE;
		break;
    }
}

    static void
cmd_with_count(
    char	*cmd,
    char_u	*bufp,
    size_t	bufsize,
    long	Prenum)
{
    if (Prenum > 0)
	vim_snprintf((char *)bufp, bufsize, "%s %ld", cmd, Prenum);
    else
	STRCPY(bufp, cmd);
}

/*
 * If "split_disallowed" is set give an error and return FAIL.
 * Otherwise return OK.
 */
    static int
check_split_disallowed(void)
{
    if (split_disallowed > 0)
    {
	emsg(_(e_cant_split_window_while_closing_another));
	return FAIL;
    }
    if (curwin->w_buffer->b_locked_split)
    {
	emsg(_(e_cannot_split_window_when_closing_buffer));
	return FAIL;
    }
    return OK;
}

/*
 * split the current window, implements CTRL-W s and :split
 *
 * "size" is the height or width for the new window, 0 to use half of current
 * height or width.
 *
 * "flags":
 * WSP_ROOM: require enough room for new window
 * WSP_VERT: vertical split.
 * WSP_TOP:  open window at the top-left of the shell (help window).
 * WSP_BOT:  open window at the bottom-right of the shell (quickfix window).
 * WSP_HELP: creating the help window, keep layout snapshot
 *
 * return FAIL for failure, OK otherwise
 */
    int
win_split(int size, int flags)
{
    if (ERROR_IF_ANY_POPUP_WINDOW)
	return FAIL;

    if (check_split_disallowed() == FAIL)
	return FAIL;

    // When the ":tab" modifier was used open a new tab page instead.
    if (may_open_tabpage() == OK)
	return OK;

    // Add flags from ":vertical", ":topleft" and ":botright".
    flags |= cmdmod.cmod_split;
    if ((flags & WSP_TOP) && (flags & WSP_BOT))
    {
	emsg(_(e_cant_split_topleft_and_botright_at_the_same_time));
	return FAIL;
    }

    // When creating the help window make a snapshot of the window layout.
    // Otherwise clear the snapshot, it's now invalid.
    if (flags & WSP_HELP)
	make_snapshot(SNAP_HELP_IDX);
    else
	clear_snapshot(curtab, SNAP_HELP_IDX);

    return win_split_ins(size, flags, NULL, 0);
}

/*
 * When "new_wp" is NULL: split the current window in two.
 * When "new_wp" is not NULL: insert this window at the far
 * top/left/right/bottom.
 * Return FAIL for failure, OK otherwise.
 */
    int
win_split_ins(
    int		size,
    int		flags,
    win_T	*new_wp,
    int		dir)
{
    win_T	*wp = new_wp;
    win_T	*oldwin;
    int		new_size = size;
    int		i;
    int		need_status = 0;
    int		do_equal = FALSE;
    int		needed;
    int		available;
    int		oldwin_height = 0;
    int		layout;
    frame_T	*frp, *curfrp, *frp2, *prevfrp;
    int		before;
    int		minheight;
    int		wmh1;
    int		did_set_fraction = FALSE;
    int		retval = FAIL;

    // Do not redraw here, curwin->w_buffer may be invalid.
    ++RedrawingDisabled;

    if (flags & WSP_TOP)
	oldwin = firstwin;
    else if (flags & WSP_BOT)
	oldwin = lastwin;
    else
	oldwin = curwin;

    // add a status line when p_ls == 1 and splitting the first window
    if (ONE_WINDOW && p_ls == 1 && oldwin->w_status_height == 0)
    {
	if (VISIBLE_HEIGHT(oldwin) <= p_wmh && new_wp == NULL)
	{
	    emsg(_(e_not_enough_room));
	    goto theend;
	}
	need_status = STATUS_HEIGHT;
    }

#ifdef FEAT_GUI
    // May be needed for the scrollbars that are going to change.
    if (gui.in_use)
	out_flush();
#endif

    if (flags & WSP_VERT)
    {
	int	wmw1;
	int	minwidth;

	layout = FR_ROW;

	/*
	 * Check if we are able to split the current window and compute its
	 * width.
	 */
	// Current window requires at least 1 space.
	wmw1 = (p_wmw == 0 ? 1 : p_wmw);
	needed = wmw1 + 1;
	if (flags & WSP_ROOM)
	    needed += p_wiw - wmw1;
	if (flags & (WSP_BOT | WSP_TOP))
	{
	    minwidth = frame_minwidth(topframe, NOWIN);
	    available = topframe->fr_width;
	    needed += minwidth;
	}
	else if (p_ea)
	{
	    minwidth = frame_minwidth(oldwin->w_frame, NOWIN);
	    prevfrp = oldwin->w_frame;
	    for (frp = oldwin->w_frame->fr_parent; frp != NULL;
							frp = frp->fr_parent)
	    {
		if (frp->fr_layout == FR_ROW)
		    FOR_ALL_FRAMES(frp2, frp->fr_child)
			if (frp2 != prevfrp)
			    minwidth += frame_minwidth(frp2, NOWIN);
		prevfrp = frp;
	    }
	    available = topframe->fr_width;
	    needed += minwidth;
	}
	else
	{
	    minwidth = frame_minwidth(oldwin->w_frame, NOWIN);
	    available = oldwin->w_frame->fr_width;
	    needed += minwidth;
	}
	if (available < needed && new_wp == NULL)
	{
	    emsg(_(e_not_enough_room));
	    goto theend;
	}
	if (new_size == 0)
	    new_size = oldwin->w_width / 2;
	if (new_size > available - minwidth - 1)
	    new_size = available - minwidth - 1;
	if (new_size < wmw1)
	    new_size = wmw1;

	// if it doesn't fit in the current window, need win_equal()
	if (oldwin->w_width - new_size - 1 < p_wmw)
	    do_equal = TRUE;

	// We don't like to take lines for the new window from a
	// 'winfixwidth' window.  Take them from a window to the left or right
	// instead, if possible. Add one for the separator.
	if (oldwin->w_p_wfw)
	    win_setwidth_win(oldwin->w_width + new_size + 1, oldwin);

	// Only make all windows the same width if one of them (except oldwin)
	// is wider than one of the split windows.
	if (!do_equal && p_ea && size == 0 && *p_ead != 'v'
					 && oldwin->w_frame->fr_parent != NULL)
	{
	    frp = oldwin->w_frame->fr_parent->fr_child;
	    while (frp != NULL)
	    {
		if (frp->fr_win != oldwin && frp->fr_win != NULL
			&& (frp->fr_win->w_width > new_size
			    || frp->fr_win->w_width > oldwin->w_width
							      - new_size - 1))
		{
		    do_equal = TRUE;
		    break;
		}
		frp = frp->fr_next;
	    }
	}
    }
    else
    {
	layout = FR_COL;

	/*
	 * Check if we are able to split the current window and compute its
	 * height.
	 */
	// Current window requires at least 1 space.
	wmh1 = (p_wmh == 0 ? 1 : p_wmh) + WINBAR_HEIGHT(curwin);
	needed = wmh1 + STATUS_HEIGHT;
	if (flags & WSP_ROOM)
	    needed += p_wh - wmh1;
	if (flags & (WSP_BOT | WSP_TOP))
	{
	    minheight = frame_minheight(topframe, NOWIN) + need_status;
	    available = topframe->fr_height;
	    needed += minheight;
	}
	else if (p_ea)
	{
	    minheight = frame_minheight(oldwin->w_frame, NOWIN) + need_status;
	    prevfrp = oldwin->w_frame;
	    for (frp = oldwin->w_frame->fr_parent; frp != NULL;
							frp = frp->fr_parent)
	    {
		if (frp->fr_layout == FR_COL)
		    FOR_ALL_FRAMES(frp2, frp->fr_child)
			if (frp2 != prevfrp)
			    minheight += frame_minheight(frp2, NOWIN);
		prevfrp = frp;
	    }
	    available = topframe->fr_height;
	    needed += minheight;
	}
	else
	{
	    minheight = frame_minheight(oldwin->w_frame, NOWIN) + need_status;
	    available = oldwin->w_frame->fr_height;
	    needed += minheight;
	}
	if (available < needed && new_wp == NULL)
	{
	    emsg(_(e_not_enough_room));
	    goto theend;
	}
	oldwin_height = oldwin->w_height;
	if (need_status)
	{
	    oldwin->w_status_height = STATUS_HEIGHT;
	    oldwin_height -= STATUS_HEIGHT;
	}
	if (new_size == 0)
	    new_size = oldwin_height / 2;
	if (new_size > available - minheight - STATUS_HEIGHT)
	    new_size = available - minheight - STATUS_HEIGHT;
	if (new_size < wmh1)
	    new_size = wmh1;

	// if it doesn't fit in the current window, need win_equal()
	if (oldwin_height - new_size - STATUS_HEIGHT < p_wmh)
	    do_equal = TRUE;

	// We don't like to take lines for the new window from a
	// 'winfixheight' window.  Take them from a window above or below
	// instead, if possible.
	if (oldwin->w_p_wfh)
	{
	    // Set w_fraction now so that the cursor keeps the same relative
	    // vertical position using the old height.
	    set_fraction(oldwin);
	    did_set_fraction = TRUE;

	    win_setheight_win(oldwin->w_height + new_size + STATUS_HEIGHT,
								      oldwin);
	    oldwin_height = oldwin->w_height;
	    if (need_status)
		oldwin_height -= STATUS_HEIGHT;
	}

	// Only make all windows the same height if one of them (except oldwin)
	// is higher than one of the split windows.
	if (!do_equal && p_ea && size == 0 && *p_ead != 'h'
	   && oldwin->w_frame->fr_parent != NULL)
	{
	    frp = oldwin->w_frame->fr_parent->fr_child;
	    while (frp != NULL)
	    {
		if (frp->fr_win != oldwin && frp->fr_win != NULL
			&& (frp->fr_win->w_height > new_size
			    || frp->fr_win->w_height > oldwin_height - new_size
							      - STATUS_HEIGHT))
		{
		    do_equal = TRUE;
		    break;
		}
		frp = frp->fr_next;
	    }
	}
    }

    /*
     * allocate new window structure and link it in the window list
     */
    if ((flags & WSP_TOP) == 0
	    && ((flags & WSP_BOT)
		|| (flags & WSP_BELOW)
		|| (!(flags & WSP_ABOVE)
		    && ( (flags & WSP_VERT) ? p_spr : p_sb))))
    {
	// new window below/right of current one
	if (new_wp == NULL)
	    wp = win_alloc(oldwin, FALSE);
	else
	    win_append(oldwin, wp);
    }
    else
    {
	if (new_wp == NULL)
	    wp = win_alloc(oldwin->w_prev, FALSE);
	else
	    win_append(oldwin->w_prev, wp);
    }

    if (new_wp == NULL)
    {
	if (wp == NULL)
	    goto theend;

	new_frame(wp);
	if (wp->w_frame == NULL)
	{
	    win_free(wp, NULL);
	    goto theend;
	}

	// make the contents of the new window the same as the current one
	win_init(wp, curwin, flags);
    }

    /*
     * Reorganise the tree of frames to insert the new window.
     */
    if (flags & (WSP_TOP | WSP_BOT))
    {
	if ((topframe->fr_layout == FR_COL && (flags & WSP_VERT) == 0)
	    || (topframe->fr_layout == FR_ROW && (flags & WSP_VERT) != 0))
	{
	    curfrp = topframe->fr_child;
	    if (flags & WSP_BOT)
		while (curfrp->fr_next != NULL)
		    curfrp = curfrp->fr_next;
	}
	else
	    curfrp = topframe;
	before = (flags & WSP_TOP);
    }
    else
    {
	curfrp = oldwin->w_frame;
	if (flags & WSP_BELOW)
	    before = FALSE;
	else if (flags & WSP_ABOVE)
	    before = TRUE;
	else if (flags & WSP_VERT)
	    before = !p_spr;
	else
	    before = !p_sb;
    }
    if (curfrp->fr_parent == NULL || curfrp->fr_parent->fr_layout != layout)
    {
	// Need to create a new frame in the tree to make a branch.
	frp = ALLOC_CLEAR_ONE(frame_T);
	*frp = *curfrp;
	curfrp->fr_layout = layout;
	frp->fr_parent = curfrp;
	frp->fr_next = NULL;
	frp->fr_prev = NULL;
	curfrp->fr_child = frp;
	curfrp->fr_win = NULL;
	curfrp = frp;
	if (frp->fr_win != NULL)
	    oldwin->w_frame = frp;
	else
	    FOR_ALL_FRAMES(frp, frp->fr_child)
		frp->fr_parent = curfrp;
    }

    if (new_wp == NULL)
	frp = wp->w_frame;
    else
	frp = new_wp->w_frame;
    frp->fr_parent = curfrp->fr_parent;

    // Insert the new frame at the right place in the frame list.
    if (before)
	frame_insert(curfrp, frp);
    else
	frame_append(curfrp, frp);

    // Set w_fraction now so that the cursor keeps the same relative
    // vertical position.
    if (!did_set_fraction)
	set_fraction(oldwin);
    wp->w_fraction = oldwin->w_fraction;

    if (flags & WSP_VERT)
    {
	wp->w_p_scr = curwin->w_p_scr;

	if (need_status)
	{
	    win_new_height(oldwin, oldwin->w_height - 1);
	    oldwin->w_status_height = need_status;
	}
	if (flags & (WSP_TOP | WSP_BOT))
	{
	    // set height and row of new window to full height
	    wp->w_winrow = tabline_height();
	    win_new_height(wp, curfrp->fr_height - (p_ls > 0)
							  - WINBAR_HEIGHT(wp));
	    wp->w_status_height = (p_ls > 0);
	}
	else
	{
	    // height and row of new window is same as current window
	    wp->w_winrow = oldwin->w_winrow;
	    win_new_height(wp, VISIBLE_HEIGHT(oldwin));
	    wp->w_status_height = oldwin->w_status_height;
	}
	frp->fr_height = curfrp->fr_height;

	// "new_size" of the current window goes to the new window, use
	// one column for the vertical separator
	win_new_width(wp, new_size);
	if (before)
	    wp->w_vsep_width = 1;
	else
	{
	    wp->w_vsep_width = oldwin->w_vsep_width;
	    oldwin->w_vsep_width = 1;
	}
	if (flags & (WSP_TOP | WSP_BOT))
	{
	    if (flags & WSP_BOT)
		frame_add_vsep(curfrp);
	    // Set width of neighbor frame
	    frame_new_width(curfrp, curfrp->fr_width
		     - (new_size + ((flags & WSP_TOP) != 0)), flags & WSP_TOP,
								       FALSE);
	}
	else
	    win_new_width(oldwin, oldwin->w_width - (new_size + 1));
	if (before)	// new window left of current one
	{
	    wp->w_wincol = oldwin->w_wincol;
	    oldwin->w_wincol += new_size + 1;
	}
	else		// new window right of current one
	    wp->w_wincol = oldwin->w_wincol + oldwin->w_width + 1;
	frame_fix_width(oldwin);
	frame_fix_width(wp);
    }
    else
    {
	// width and column of new window is same as current window
	if (flags & (WSP_TOP | WSP_BOT))
	{
	    wp->w_wincol = 0;
	    win_new_width(wp, Columns);
	    wp->w_vsep_width = 0;
	}
	else
	{
	    wp->w_wincol = oldwin->w_wincol;
	    win_new_width(wp, oldwin->w_width);
	    wp->w_vsep_width = oldwin->w_vsep_width;
	}
	frp->fr_width = curfrp->fr_width;

	// "new_size" of the current window goes to the new window, use
	// one row for the status line
	win_new_height(wp, new_size);
	int old_status_height = oldwin->w_status_height;
	if (flags & (WSP_TOP | WSP_BOT))
	{
	    int new_fr_height = curfrp->fr_height - new_size
							  + WINBAR_HEIGHT(wp) ;

	    if (!((flags & WSP_BOT) && p_ls == 0))
		new_fr_height -= STATUS_HEIGHT;
	    if (flags & WSP_BOT)
		frame_add_statusline(curfrp);
	    frame_new_height(curfrp, new_fr_height, flags & WSP_TOP, FALSE);
	}
	else
	    win_new_height(oldwin, oldwin_height - (new_size + STATUS_HEIGHT));
	if (before)	// new window above current one
	{
	    wp->w_winrow = oldwin->w_winrow;
	    wp->w_status_height = STATUS_HEIGHT;
	    oldwin->w_winrow += wp->w_height + STATUS_HEIGHT;
	}
	else		// new window below current one
	{
	    wp->w_winrow = oldwin->w_winrow + VISIBLE_HEIGHT(oldwin)
							       + STATUS_HEIGHT;
	    wp->w_status_height = old_status_height;
	    if (!(flags & WSP_BOT))
		oldwin->w_status_height = STATUS_HEIGHT;
	}
	frame_fix_height(wp);
	frame_fix_height(oldwin);
    }

    if (flags & (WSP_TOP | WSP_BOT))
	(void)win_comp_pos();

     // Both windows need redrawing.  Update all status lines, in case they
     // show something related to the window count or position.
    redraw_win_later(wp, UPD_NOT_VALID);
    redraw_win_later(oldwin, UPD_NOT_VALID);
    status_redraw_all();

    if (need_status)
    {
	msg_row = Rows - 1;
	msg_col = sc_col;
	msg_clr_eos_force();	// Old command/ruler may still be there
	comp_col();
	msg_row = Rows - 1;
	msg_col = 0;	// put position back at start of line
    }

    /*
     * equalize the window sizes.
     */
    if (do_equal || dir != 0)
	win_equal(wp, TRUE,
		(flags & WSP_VERT) ? (dir == 'v' ? 'b' : 'h')
		: dir == 'h' ? 'b' : 'v');
    else if (!is_aucmd_win(wp))
	win_fix_scroll(FALSE);

    // Don't change the window height/width to 'winheight' / 'winwidth' if a
    // size was given.
    if (flags & WSP_VERT)
    {
	i = p_wiw;
	if (size != 0)
	    p_wiw = size;

# ifdef FEAT_GUI
	// When 'guioptions' includes 'L' or 'R' may have to add scrollbars.
	if (gui.in_use)
	    gui_init_which_components(NULL);
# endif
    }
    else
    {
	i = p_wh;
	if (size != 0)
	    p_wh = size;
    }

    /*
     * make the new window the current window
     */
    (void)win_enter_ext(wp, WEE_TRIGGER_NEW_AUTOCMDS
		    | WEE_TRIGGER_ENTER_AUTOCMDS | WEE_TRIGGER_LEAVE_AUTOCMDS);
    if (flags & WSP_VERT)
	p_wiw = i;
    else
	p_wh = i;
    retval = OK;

theend:
    if (RedrawingDisabled > 0)
	--RedrawingDisabled;
    return retval;
}


/*
 * Initialize window "newp" from window "oldp".
 * Used when splitting a window and when creating a new tab page.
 * The windows will both edit the same buffer.
 * WSP_NEWLOC may be specified in flags to prevent the location list from
 * being copied.
 */
    static void
win_init(win_T *newp, win_T *oldp, int flags UNUSED)
{
    int		i;

    newp->w_buffer = oldp->w_buffer;
#ifdef FEAT_SYN_HL
    newp->w_s = &(oldp->w_buffer->b_s);
#endif
    oldp->w_buffer->b_nwindows++;
    newp->w_cursor = oldp->w_cursor;
    newp->w_valid = 0;
    newp->w_curswant = oldp->w_curswant;
    newp->w_set_curswant = oldp->w_set_curswant;
    newp->w_topline = oldp->w_topline;
#ifdef FEAT_DIFF
    newp->w_topfill = oldp->w_topfill;
#endif
    newp->w_leftcol = oldp->w_leftcol;
    newp->w_pcmark = oldp->w_pcmark;
    newp->w_prev_pcmark = oldp->w_prev_pcmark;
    newp->w_alt_fnum = oldp->w_alt_fnum;
    newp->w_wrow = oldp->w_wrow;
    newp->w_fraction = oldp->w_fraction;
    newp->w_prev_fraction_row = oldp->w_prev_fraction_row;
    copy_jumplist(oldp, newp);
#ifdef FEAT_QUICKFIX
    if (flags & WSP_NEWLOC)
    {
	// Don't copy the location list.
	newp->w_llist = NULL;
	newp->w_llist_ref = NULL;
    }
    else
	copy_loclist_stack(oldp, newp);
#endif
    newp->w_localdir = (oldp->w_localdir == NULL)
				    ? NULL : vim_strsave(oldp->w_localdir);
    newp->w_prevdir = (oldp->w_prevdir == NULL)
				    ? NULL : vim_strsave(oldp->w_prevdir);

    if (*p_spk != 'c')
    {
	if (*p_spk == 't')
	    newp->w_skipcol = oldp->w_skipcol;
	newp->w_botline = oldp->w_botline;
	newp->w_prev_height = oldp->w_height - WINBAR_HEIGHT(oldp);
	newp->w_prev_winrow = oldp->w_winrow + 2 * WINBAR_HEIGHT(oldp);
    }

    // copy tagstack and folds
    for (i = 0; i < oldp->w_tagstacklen; i++)
    {
	taggy_T	*tag = &newp->w_tagstack[i];
	*tag = oldp->w_tagstack[i];
	if (tag->tagname != NULL)
	    tag->tagname = vim_strsave(tag->tagname);
	if (tag->user_data != NULL)
	    tag->user_data = vim_strsave(tag->user_data);
    }
    newp->w_tagstackidx = oldp->w_tagstackidx;
    newp->w_tagstacklen = oldp->w_tagstacklen;

    // Keep same changelist position in new window.
    newp->w_changelistidx = oldp->w_changelistidx;

#ifdef FEAT_FOLDING
    copyFoldingState(oldp, newp);
#endif

    win_init_some(newp, oldp);
#ifdef FEAT_TERMINAL
    term_update_wincolor(newp);
#endif
}

/*
 * Initialize window "newp" from window "old".
 * Only the essential things are copied.
 */
    static void
win_init_some(win_T *newp, win_T *oldp)
{
    // Use the same argument list.
    newp->w_alist = oldp->w_alist;
    ++newp->w_alist->al_refcount;
    newp->w_arg_idx = oldp->w_arg_idx;

    // copy options from existing window
    win_copy_options(oldp, newp);
}

/*
 * Return TRUE if "win" is a global popup or a popup in the current tab page.
 */
    int
win_valid_popup(win_T *win UNUSED)
{
#ifdef FEAT_PROP_POPUP
    win_T	*wp;

    FOR_ALL_POPUPWINS(wp)
	if (wp == win)
	    return TRUE;
    FOR_ALL_POPUPWINS_IN_TAB(curtab, wp)
	if (wp == win)
	    return TRUE;
#endif
    return FALSE;
}

/*
 * Check if "win" is a pointer to an existing window in the current tab page.
 */
    int
win_valid(win_T *win)
{
    win_T	*wp;

    if (win == NULL)
	return FALSE;
    FOR_ALL_WINDOWS(wp)
	if (wp == win)
	    return TRUE;
    return win_valid_popup(win);
}

/*
 * Find window "id" in the current tab page.
 * Also find popup windows.
 * Return NULL if not found.
 */
    win_T *
win_find_by_id(int id)
{
    win_T   *wp;

    FOR_ALL_WINDOWS(wp)
	if (wp->w_id == id)
	    return wp;
#ifdef FEAT_PROP_POPUP
    FOR_ALL_POPUPWINS(wp)
	if (wp->w_id == id)
	    return wp;
    FOR_ALL_POPUPWINS_IN_TAB(curtab, wp)
	if (wp->w_id == id)
	    return wp;
#endif
    return NULL;
}

/*
 * Check if "win" is a pointer to an existing window in any tab page.
 */
    int
win_valid_any_tab(win_T *win)
{
    win_T	*wp;
    tabpage_T	*tp;

    if (win == NULL)
	return FALSE;
    FOR_ALL_TABPAGES(tp)
    {
	FOR_ALL_WINDOWS_IN_TAB(tp, wp)
	{
	    if (wp == win)
		return TRUE;
	}
#ifdef FEAT_PROP_POPUP
	FOR_ALL_POPUPWINS_IN_TAB(tp, wp)
	    if (wp == win)
		return TRUE;
#endif
    }
    return win_valid_popup(win);
}

/*
 * Return the number of windows.
 */
    int
win_count(void)
{
    win_T	*wp;
    int		count = 0;

    FOR_ALL_WINDOWS(wp)
	++count;
    return count;
}

/*
 * Make "count" windows on the screen.
 * Return actual number of windows on the screen.
 * Must be called when there is just one window, filling the whole screen
 * (excluding the command line).
 */
    int
make_windows(
    int		count,
    int		vertical UNUSED)  // split windows vertically if TRUE
{
    int		maxcount;
    int		todo;

    if (vertical)
    {
	// Each window needs at least 'winminwidth' lines and a separator
	// column.
	maxcount = (curwin->w_width + curwin->w_vsep_width
					     - (p_wiw - p_wmw)) / (p_wmw + 1);
    }
    else
    {
	// Each window needs at least 'winminheight' lines and a status line.
	maxcount = (VISIBLE_HEIGHT(curwin) + curwin->w_status_height
				  - (p_wh - p_wmh)) / (p_wmh + STATUS_HEIGHT);
    }

    if (maxcount < 2)
	maxcount = 2;
    if (count > maxcount)
	count = maxcount;

    /*
     * add status line now, otherwise first window will be too big
     */
    if (count > 1)
	last_status(TRUE);

    /*
     * Don't execute autocommands while creating the windows.  Must do that
     * when putting the buffers in the windows.
     */
    block_autocmds();

    // todo is number of windows left to create
    for (todo = count - 1; todo > 0; --todo)
	if (vertical)
	{
	    if (win_split(curwin->w_width - (curwin->w_width - todo)
			/ (todo + 1) - 1, WSP_VERT | WSP_ABOVE) == FAIL)
		break;
	}
	else
	{
	    if (win_split(curwin->w_height - (curwin->w_height - todo
			    * STATUS_HEIGHT) / (todo + 1)
			- STATUS_HEIGHT, WSP_ABOVE) == FAIL)
		break;
	}

    unblock_autocmds();

    // return actual number of windows
    return (count - todo);
}

/*
 * Exchange current and next window
 */
    static void
win_exchange(long Prenum)
{
    frame_T	*frp;
    frame_T	*frp2;
    win_T	*wp;
    win_T	*wp2;
    int		temp;

    if (ERROR_IF_ANY_POPUP_WINDOW)
	return;
    if (ONE_WINDOW)	    // just one window
    {
	beep_flush();
	return;
    }
    if (text_or_buf_locked())
    {
	beep_flush();
	return;
    }

#ifdef FEAT_GUI
    need_mouse_correct = TRUE;
#endif

    /*
     * find window to exchange with
     */
    if (Prenum)
    {
	frp = curwin->w_frame->fr_parent->fr_child;
	while (frp != NULL && --Prenum > 0)
	    frp = frp->fr_next;
    }
    else if (curwin->w_frame->fr_next != NULL)	// Swap with next
	frp = curwin->w_frame->fr_next;
    else    // Swap last window in row/col with previous
	frp = curwin->w_frame->fr_prev;

    // We can only exchange a window with another window, not with a frame
    // containing windows.
    if (frp == NULL || frp->fr_win == NULL || frp->fr_win == curwin)
	return;
    wp = frp->fr_win;

/*
 * 1. remove curwin from the list. Remember after which window it was in wp2
 * 2. insert curwin before wp in the list
 * if wp != wp2
 *    3. remove wp from the list
 *    4. insert wp after wp2
 * 5. exchange the status line height and vsep width.
 */
    wp2 = curwin->w_prev;
    frp2 = curwin->w_frame->fr_prev;
    if (wp->w_prev != curwin)
    {
	win_remove(curwin, NULL);
	frame_remove(curwin->w_frame);
	win_append(wp->w_prev, curwin);
	frame_insert(frp, curwin->w_frame);
    }
    if (wp != wp2)
    {
	win_remove(wp, NULL);
	frame_remove(wp->w_frame);
	win_append(wp2, wp);
	if (frp2 == NULL)
	    frame_insert(wp->w_frame->fr_parent->fr_child, wp->w_frame);
	else
	    frame_append(frp2, wp->w_frame);
    }
    temp = curwin->w_status_height;
    curwin->w_status_height = wp->w_status_height;
    wp->w_status_height = temp;
    temp = curwin->w_vsep_width;
    curwin->w_vsep_width = wp->w_vsep_width;
    wp->w_vsep_width = temp;

    frame_fix_height(curwin);
    frame_fix_height(wp);
    frame_fix_width(curwin);
    frame_fix_width(wp);

    (void)win_comp_pos();		// recompute window positions

    if (wp->w_buffer != curbuf)
	reset_VIsual_and_resel();
    else if (VIsual_active)
	wp->w_cursor = curwin->w_cursor;

    win_enter(wp, TRUE);
    redraw_all_later(UPD_NOT_VALID);
}

/*
 * rotate windows: if upwards TRUE the second window becomes the first one
 *		   if upwards FALSE the first window becomes the second one
 */
    static void
win_rotate(int upwards, int count)
{
    win_T	*wp1;
    win_T	*wp2;
    frame_T	*frp;
    int		n;

    if (ONE_WINDOW)		// nothing to do
    {
	beep_flush();
	return;
    }

#ifdef FEAT_GUI
    need_mouse_correct = TRUE;
#endif

    // Check if all frames in this row/col have one window.
    FOR_ALL_FRAMES(frp, curwin->w_frame->fr_parent->fr_child)
	if (frp->fr_win == NULL)
	{
	    emsg(_(e_cannot_rotate_when_another_window_is_split));
	    return;
	}

    while (count--)
    {
	if (upwards)		// first window becomes last window
	{
	    // remove first window/frame from the list
	    frp = curwin->w_frame->fr_parent->fr_child;
	    wp1 = frp->fr_win;
	    win_remove(wp1, NULL);
	    frame_remove(frp);

	    // find last frame and append removed window/frame after it
	    for ( ; frp->fr_next != NULL; frp = frp->fr_next)
		;
	    win_append(frp->fr_win, wp1);
	    frame_append(frp, wp1->w_frame);

	    wp2 = frp->fr_win;		// previously last window
	}
	else			// last window becomes first window
	{
	    // find last window/frame in the list and remove it
	    for (frp = curwin->w_frame; frp->fr_next != NULL;
							   frp = frp->fr_next)
		;
	    wp1 = frp->fr_win;
	    wp2 = wp1->w_prev;		    // will become last window
	    win_remove(wp1, NULL);
	    frame_remove(frp);

	    // append the removed window/frame before the first in the list
	    win_append(frp->fr_parent->fr_child->fr_win->w_prev, wp1);
	    frame_insert(frp->fr_parent->fr_child, frp);
	}

	// exchange status height and vsep width of old and new last window
	n = wp2->w_status_height;
	wp2->w_status_height = wp1->w_status_height;
	wp1->w_status_height = n;
	frame_fix_height(wp1);
	frame_fix_height(wp2);
	n = wp2->w_vsep_width;
	wp2->w_vsep_width = wp1->w_vsep_width;
	wp1->w_vsep_width = n;
	frame_fix_width(wp1);
	frame_fix_width(wp2);

	// recompute w_winrow and w_wincol for all windows
	(void)win_comp_pos();
    }

    redraw_all_later(UPD_NOT_VALID);
}

/*
 * Move the current window to the very top/bottom/left/right of the screen.
 */
    static void
win_totop(int size, int flags)
{
    int		dir;
    int		height = curwin->w_height;

    if (ONE_WINDOW)
    {
	beep_flush();
	return;
    }
    if (check_split_disallowed() == FAIL)
	return;

    // Remove the window and frame from the tree of frames.
    (void)winframe_remove(curwin, &dir, NULL);
    win_remove(curwin, NULL);
    last_status(FALSE);	    // may need to remove last status line
    (void)win_comp_pos();   // recompute window positions

    // Split a window on the desired side and put the window there.
    (void)win_split_ins(size, flags, curwin, dir);
    if (!(flags & WSP_VERT))
    {
	win_setheight(height);
	if (p_ea)
	    win_equal(curwin, TRUE, 'v');
    }

#if defined(FEAT_GUI)
    // When 'guioptions' includes 'L' or 'R' may have to remove or add
    // scrollbars.  Have to update them anyway.
    gui_may_update_scrollbars();
#endif
}

/*
 * Move window "win1" to below/right of "win2" and make "win1" the current
 * window.  Only works within the same frame!
 */
    void
win_move_after(win_T *win1, win_T *win2)
{
    int		height;

    // check if the arguments are reasonable
    if (win1 == win2)
	return;

    // check if there is something to do
    if (win2->w_next != win1)
    {
	if (win1->w_frame->fr_parent != win2->w_frame->fr_parent)
	{
	    iemsg("Trying to move a window into another frame");
	    return;
	}

	// may need to move the status line/vertical separator of the last
	// window
	if (win1 == lastwin)
	{
	    height = win1->w_prev->w_status_height;
	    win1->w_prev->w_status_height = win1->w_status_height;
	    win1->w_status_height = height;
	    if (win1->w_prev->w_vsep_width == 1)
	    {
		// Remove the vertical separator from the last-but-one window,
		// add it to the last window.  Adjust the frame widths.
		win1->w_prev->w_vsep_width = 0;
		win1->w_prev->w_frame->fr_width -= 1;
		win1->w_vsep_width = 1;
		win1->w_frame->fr_width += 1;
	    }
	}
	else if (win2 == lastwin)
	{
	    height = win1->w_status_height;
	    win1->w_status_height = win2->w_status_height;
	    win2->w_status_height = height;
	    if (win1->w_vsep_width == 1)
	    {
		// Remove the vertical separator from win1, add it to the last
		// window, win2.  Adjust the frame widths.
		win2->w_vsep_width = 1;
		win2->w_frame->fr_width += 1;
		win1->w_vsep_width = 0;
		win1->w_frame->fr_width -= 1;
	    }
	}
	win_remove(win1, NULL);
	frame_remove(win1->w_frame);
	win_append(win2, win1);
	frame_append(win2->w_frame, win1->w_frame);

	(void)win_comp_pos();	// recompute w_winrow for all windows
	redraw_later(UPD_NOT_VALID);
    }
    win_enter(win1, FALSE);
}

/*
 * Make all windows the same height.
 * 'next_curwin' will soon be the current window, make sure it has enough
 * rows.
 */
    void
win_equal(
    win_T	*next_curwin,	// pointer to current window to be or NULL
    int		current,	// do only frame with current window
    int		dir)		// 'v' for vertically, 'h' for horizontally,
				// 'b' for both, 0 for using p_ead
{
    if (dir == 0)
	dir = *p_ead;
    win_equal_rec(next_curwin == NULL ? curwin : next_curwin, current,
		      topframe, dir, 0, tabline_height(),
					   (int)Columns, topframe->fr_height);
    if (!is_aucmd_win(next_curwin))
	win_fix_scroll(TRUE);
}

/*
 * Set a frame to a new position and height, spreading the available room
 * equally over contained frames.
 * The window "next_curwin" (if not NULL) should at least get the size from
 * 'winheight' and 'winwidth' if possible.
 */
    static void
win_equal_rec(
    win_T	*next_curwin,	// pointer to current window to be or NULL
    int		current,	// do only frame with current window
    frame_T	*topfr,		// frame to set size off
    int		dir,		// 'v', 'h' or 'b', see win_equal()
    int		col,		// horizontal position for frame
    int		row,		// vertical position for frame
    int		width,		// new width of frame
    int		height)		// new height of frame
{
    int		n, m;
    int		extra_sep = 0;
    int		wincount, totwincount = 0;
    frame_T	*fr;
    int		next_curwin_size = 0;
    int		room = 0;
    int		new_size;
    int		has_next_curwin = 0;
    int		hnc;

    if (topfr->fr_layout == FR_LEAF)
    {
	// Set the width/height of this frame.
	// Redraw when size or position changes
	if (topfr->fr_height != height || topfr->fr_win->w_winrow != row
		|| topfr->fr_width != width || topfr->fr_win->w_wincol != col
	   )
	{
	    topfr->fr_win->w_winrow = row;
	    frame_new_height(topfr, height, FALSE, FALSE);
	    topfr->fr_win->w_wincol = col;
	    frame_new_width(topfr, width, FALSE, FALSE);
	    redraw_all_later(UPD_NOT_VALID);
	}
    }
    else if (topfr->fr_layout == FR_ROW)
    {
	topfr->fr_width = width;
	topfr->fr_height = height;

	if (dir != 'v')			// equalize frame widths
	{
	    // Compute the maximum number of windows horizontally in this
	    // frame.
	    n = frame_minwidth(topfr, NOWIN);
	    // add one for the rightmost window, it doesn't have a separator
	    if (col + width == Columns)
		extra_sep = 1;
	    else
		extra_sep = 0;
	    totwincount = (n + extra_sep) / (p_wmw + 1);
	    has_next_curwin = frame_has_win(topfr, next_curwin);

	    /*
	     * Compute width for "next_curwin" window and room available for
	     * other windows.
	     * "m" is the minimal width when counting p_wiw for "next_curwin".
	     */
	    m = frame_minwidth(topfr, next_curwin);
	    room = width - m;
	    if (room < 0)
	    {
		next_curwin_size = p_wiw + room;
		room = 0;
	    }
	    else
	    {
		next_curwin_size = -1;
		FOR_ALL_FRAMES(fr, topfr->fr_child)
		{
		    if (!frame_fixed_width(fr))
			continue;
		    // If 'winfixwidth' set keep the window width if possible.
		    // Watch out for this window being the next_curwin.
		    n = frame_minwidth(fr, NOWIN);
		    new_size = fr->fr_width;
		    if (frame_has_win(fr, next_curwin))
		    {
			room += p_wiw - p_wmw;
			next_curwin_size = 0;
			if (new_size < p_wiw)
			    new_size = p_wiw;
		    }
		    else
			// These windows don't use up room.
			totwincount -= (n + (fr->fr_next == NULL
					       ? extra_sep : 0)) / (p_wmw + 1);
		    room -= new_size - n;
		    if (room < 0)
		    {
			new_size += room;
			room = 0;
		    }
		    fr->fr_newwidth = new_size;
		}
		if (next_curwin_size == -1)
		{
		    if (!has_next_curwin)
			next_curwin_size = 0;
		    else if (totwincount > 1
			    && (room + (totwincount - 2))
						  / (totwincount - 1) > p_wiw)
		    {
			// Can make all windows wider than 'winwidth', spread
			// the room equally.
			next_curwin_size = (room + p_wiw
					    + (totwincount - 1) * p_wmw
					    + (totwincount - 1)) / totwincount;
			room -= next_curwin_size - p_wiw;
		    }
		    else
			next_curwin_size = p_wiw;
		}
	    }

	    if (has_next_curwin)
		--totwincount;		// don't count curwin
	}

	FOR_ALL_FRAMES(fr, topfr->fr_child)
	{
	    wincount = 1;
	    if (fr->fr_next == NULL)
		// last frame gets all that remains (avoid roundoff error)
		new_size = width;
	    else if (dir == 'v')
		new_size = fr->fr_width;
	    else if (frame_fixed_width(fr))
	    {
		new_size = fr->fr_newwidth;
		wincount = 0;	    // doesn't count as a sizeable window
	    }
	    else
	    {
		// Compute the maximum number of windows horiz. in "fr".
		n = frame_minwidth(fr, NOWIN);
		wincount = (n + (fr->fr_next == NULL ? extra_sep : 0))
								/ (p_wmw + 1);
		m = frame_minwidth(fr, next_curwin);
		if (has_next_curwin)
		    hnc = frame_has_win(fr, next_curwin);
		else
		    hnc = FALSE;
		if (hnc)	    // don't count next_curwin
		    --wincount;
		if (totwincount == 0)
		    new_size = room;
		else
		    new_size = (wincount * room + ((unsigned)totwincount >> 1))
								/ totwincount;
		if (hnc)	    // add next_curwin size
		{
		    next_curwin_size -= p_wiw - (m - n);
		    if (next_curwin_size < 0)
			next_curwin_size = 0;
		    new_size += next_curwin_size;
		    room -= new_size - next_curwin_size;
		}
		else
		    room -= new_size;
		new_size += n;
	    }

	    // Skip frame that is full width when splitting or closing a
	    // window, unless equalizing all frames.
	    if (!current || dir != 'v' || topfr->fr_parent != NULL
		    || (new_size != fr->fr_width)
		    || frame_has_win(fr, next_curwin))
		win_equal_rec(next_curwin, current, fr, dir, col, row,
							    new_size, height);
	    col += new_size;
	    width -= new_size;
	    totwincount -= wincount;
	}
    }
    else // topfr->fr_layout == FR_COL
    {
	topfr->fr_width = width;
	topfr->fr_height = height;

	if (dir != 'h')			// equalize frame heights
	{
	    // Compute maximum number of windows vertically in this frame.
	    n = frame_minheight(topfr, NOWIN);
	    // add one for the bottom window if it doesn't have a statusline
	    if (row + height == cmdline_row && p_ls == 0)
		extra_sep = 1;
	    else
		extra_sep = 0;
	    totwincount = (n + extra_sep) / (p_wmh + 1);
	    has_next_curwin = frame_has_win(topfr, next_curwin);

	    /*
	     * Compute height for "next_curwin" window and room available for
	     * other windows.
	     * "m" is the minimal height when counting p_wh for "next_curwin".
	     */
	    m = frame_minheight(topfr, next_curwin);
	    room = height - m;
	    if (room < 0)
	    {
		// The room is less than 'winheight', use all space for the
		// current window.
		next_curwin_size = p_wh + room;
		room = 0;
	    }
	    else
	    {
		next_curwin_size = -1;
		FOR_ALL_FRAMES(fr, topfr->fr_child)
		{
		    if (!frame_fixed_height(fr))
			continue;
		    // If 'winfixheight' set keep the window height if
		    // possible.
		    // Watch out for this window being the next_curwin.
		    n = frame_minheight(fr, NOWIN);
		    new_size = fr->fr_height;
		    if (frame_has_win(fr, next_curwin))
		    {
			room += p_wh - p_wmh;
			next_curwin_size = 0;
			if (new_size < p_wh)
			    new_size = p_wh;
		    }
		    else
			// These windows don't use up room.
			totwincount -= (n + (fr->fr_next == NULL
					       ? extra_sep : 0)) / (p_wmh + 1);
		    room -= new_size - n;
		    if (room < 0)
		    {
			new_size += room;
			room = 0;
		    }
		    fr->fr_newheight = new_size;
		}
		if (next_curwin_size == -1)
		{
		    if (!has_next_curwin)
			next_curwin_size = 0;
		    else if (totwincount > 1
			    && (room + (totwincount - 2))
						   / (totwincount - 1) > p_wh)
		    {
			// can make all windows higher than 'winheight',
			// spread the room equally.
			next_curwin_size = (room + p_wh
					   + (totwincount - 1) * p_wmh
					   + (totwincount - 1)) / totwincount;
			room -= next_curwin_size - p_wh;
		    }
		    else
			next_curwin_size = p_wh;
		}
	    }

	    if (has_next_curwin)
		--totwincount;		// don't count curwin
	}

	FOR_ALL_FRAMES(fr, topfr->fr_child)
	{
	    wincount = 1;
	    if (fr->fr_next == NULL)
		// last frame gets all that remains (avoid roundoff error)
		new_size = height;
	    else if (dir == 'h')
		new_size = fr->fr_height;
	    else if (frame_fixed_height(fr))
	    {
		new_size = fr->fr_newheight;
		wincount = 0;	    // doesn't count as a sizeable window
	    }
	    else
	    {
		// Compute the maximum number of windows vert. in "fr".
		n = frame_minheight(fr, NOWIN);
		wincount = (n + (fr->fr_next == NULL ? extra_sep : 0))
								/ (p_wmh + 1);
		m = frame_minheight(fr, next_curwin);
		if (has_next_curwin)
		    hnc = frame_has_win(fr, next_curwin);
		else
		    hnc = FALSE;
		if (hnc)	    // don't count next_curwin
		    --wincount;
		if (totwincount == 0)
		    new_size = room;
		else
		    new_size = (wincount * room + ((unsigned)totwincount >> 1))
								/ totwincount;
		if (hnc)	    // add next_curwin size
		{
		    next_curwin_size -= p_wh - (m - n);
		    new_size += next_curwin_size;
		    room -= new_size - next_curwin_size;
		}
		else
		    room -= new_size;
		new_size += n;
	    }
	    // Skip frame that is full width when splitting or closing a
	    // window, unless equalizing all frames.
	    if (!current || dir != 'h' || topfr->fr_parent != NULL
		    || (new_size != fr->fr_height)
		    || frame_has_win(fr, next_curwin))
		win_equal_rec(next_curwin, current, fr, dir, col, row,
							     width, new_size);
	    row += new_size;
	    height -= new_size;
	    totwincount -= wincount;
	}
    }
}

#ifdef FEAT_JOB_CHANNEL
    void
leaving_window(win_T *win)
{
    // Only matters for a prompt window.
    if (!bt_prompt(win->w_buffer))
	return;

    // When leaving a prompt window stop Insert mode and perhaps restart
    // it when entering that window again.
    win->w_buffer->b_prompt_insert = restart_edit;
    if (restart_edit != 0 && mode_displayed)
	clear_cmdline = TRUE;		// unshow mode later
    restart_edit = NUL;

    // When leaving the window (or closing the window) was done from a
    // callback we need to break out of the Insert mode loop and restart Insert
    // mode when entering the window again.
    if (State & MODE_INSERT)
    {
	stop_insert_mode = TRUE;
	if (win->w_buffer->b_prompt_insert == NUL)
	    win->w_buffer->b_prompt_insert = 'A';
    }
}

    void
entering_window(win_T *win)
{
    // Only matters for a prompt window.
    if (!bt_prompt(win->w_buffer))
	return;

    // When switching to a prompt buffer that was in Insert mode, don't stop
    // Insert mode, it may have been set in leaving_window().
    if (win->w_buffer->b_prompt_insert != NUL)
	stop_insert_mode = FALSE;

    // When entering the prompt window restart Insert mode if we were in Insert
    // mode when we left it and not already in Insert mode.
    if ((State & MODE_INSERT) == 0)
	restart_edit = win->w_buffer->b_prompt_insert;
}
#endif

    static void
win_init_empty(win_T *wp)
{
    redraw_win_later(wp, UPD_NOT_VALID);
    wp->w_lines_valid = 0;
    wp->w_cursor.lnum = 1;
    wp->w_curswant = wp->w_cursor.col = 0;
    wp->w_cursor.coladd = 0;
    wp->w_pcmark.lnum = 1;	// pcmark not cleared but set to line 1
    wp->w_pcmark.col = 0;
    wp->w_prev_pcmark.lnum = 0;
    wp->w_prev_pcmark.col = 0;
    wp->w_topline = 1;
#ifdef FEAT_DIFF
    wp->w_topfill = 0;
#endif
    wp->w_botline = 2;
#if defined(FEAT_SYN_HL) || defined(FEAT_SPELL)
    wp->w_s = &wp->w_buffer->b_s;
#endif
#ifdef FEAT_TERMINAL
    term_reset_wincolor(wp);
#endif
}

/*
 * Init the current window "curwin".
 * Called when a new file is being edited.
 */
    void
curwin_init(void)
{
    win_init_empty(curwin);
}

/*
 * Close all windows for buffer "buf".
 */
    void
close_windows(
    buf_T	*buf,
    int		keep_curwin)	    // don't close "curwin"
{
    win_T	*wp;
    tabpage_T   *tp, *nexttp;
    int		count = tabpage_index(NULL);

    ++RedrawingDisabled;

    for (wp = firstwin; wp != NULL && !ONE_WINDOW; )
    {
	if (wp->w_buffer == buf && (!keep_curwin || wp != curwin)
		&& !(wp->w_closing || wp->w_buffer->b_locked > 0))
	{
	    if (win_close(wp, FALSE) == FAIL)
		// If closing the window fails give up, to avoid looping
		// forever.
		break;

	    // Start all over, autocommands may change the window layout.
	    wp = firstwin;
	}
	else
	    wp = wp->w_next;
    }

    // Also check windows in other tab pages.
    for (tp = first_tabpage; tp != NULL; tp = nexttp)
    {
	nexttp = tp->tp_next;
	if (tp != curtab)
	    FOR_ALL_WINDOWS_IN_TAB(tp, wp)
		if (wp->w_buffer == buf
		    && !(wp->w_closing || wp->w_buffer->b_locked > 0))
		{
		    win_close_othertab(wp, FALSE, tp);

		    // Start all over, the tab page may be closed and
		    // autocommands may change the window layout.
		    nexttp = first_tabpage;
		    break;
		}
    }

    if (RedrawingDisabled > 0)
	--RedrawingDisabled;

    if (count != tabpage_index(NULL))
	apply_autocmds(EVENT_TABCLOSED, NULL, NULL, FALSE, curbuf);
}

/*
 * Return TRUE if the current window is the only window that exists (ignoring
 * "aucmd_win[]").
 * Returns FALSE if there is a window, possibly in another tab page.
 */
    static int
last_window(void)
{
    return (one_window() && first_tabpage->tp_next == NULL);
}

/*
 * Return TRUE if there is only one window other than "aucmd_win[]" in the
 * current tab page.
 */
    int
one_window(void)
{
    win_T	*wp;
    int		seen_one = FALSE;

    FOR_ALL_WINDOWS(wp)
    {
	if (!is_aucmd_win(wp))
	{
	    if (seen_one)
		return FALSE;
	    seen_one = TRUE;
	}
    }
    return TRUE;
}

/*
 * Close the possibly last window in a tab page.
 * Returns TRUE when the window was closed already.
 */
    static int
close_last_window_tabpage(
    win_T	*win,
    int		free_buf,
    tabpage_T   *prev_curtab)
{
    if (!ONE_WINDOW)
	return FALSE;

    buf_T	*old_curbuf = curbuf;

    /*
     * Closing the last window in a tab page.  First go to another tab
     * page and then close the window and the tab page.  This avoids that
     * curwin and curtab are invalid while we are freeing memory, they may
     * be used in GUI events.
     * Don't trigger autocommands yet, they may use wrong values, so do
     * that below.
     */
    goto_tabpage_tp(alt_tabpage(), FALSE, TRUE);

    // Safety check: Autocommands may have closed the window when jumping
    // to the other tab page.
    if (valid_tabpage(prev_curtab) && prev_curtab->tp_firstwin == win)
	win_close_othertab(win, free_buf, prev_curtab);
#ifdef FEAT_JOB_CHANNEL
    entering_window(curwin);
#endif
    // Since goto_tabpage_tp above did not trigger *Enter autocommands, do
    // that now.
    apply_autocmds(EVENT_TABCLOSED, NULL, NULL, FALSE, curbuf);
    apply_autocmds(EVENT_WINENTER, NULL, NULL, FALSE, curbuf);
    apply_autocmds(EVENT_TABENTER, NULL, NULL, FALSE, curbuf);
    if (old_curbuf != curbuf)
	apply_autocmds(EVENT_BUFENTER, NULL, NULL, FALSE, curbuf);
    return TRUE;
}

/*
 * Close the buffer of "win" and unload it if "action" is DOBUF_UNLOAD.
 * "action" can also be zero (do nothing) or DOBUF_WIPE.
 * "abort_if_last" is passed to close_buffer(): abort closing if all other
 * windows are closed.
 */
    static void
win_close_buffer(win_T *win, int action, int abort_if_last)
{
#ifdef FEAT_SYN_HL
    // Free independent synblock before the buffer is freed.
    if (win->w_buffer != NULL)
	reset_synblock(win);
#endif

#ifdef FEAT_QUICKFIX
    // When a quickfix/location list window is closed and the buffer is
    // displayed in only one window, then unlist the buffer.
    if (win->w_buffer != NULL && bt_quickfix(win->w_buffer)
					&& win->w_buffer->b_nwindows == 1)
	win->w_buffer->b_p_bl = FALSE;
#endif

    // Close the link to the buffer.
    if (win->w_buffer != NULL)
    {
	bufref_T    bufref;

	set_bufref(&bufref, curbuf);
	win->w_closing = TRUE;
	close_buffer(win, win->w_buffer, action, abort_if_last, TRUE);
	if (win_valid_any_tab(win))
	    win->w_closing = FALSE;
	// Make sure curbuf is valid. It can become invalid if 'bufhidden' is
	// "wipe".
	if (!bufref_valid(&bufref))
	    curbuf = firstbuf;
    }
}

/*
 * Close window "win".  Only works for the current tab page.
 * If "free_buf" is TRUE related buffer may be unloaded.
 *
 * Called by :quit, :close, :xit, :wq and findtag().
 * Returns FAIL when the window was not closed.
 */
    int
win_close(win_T *win, int free_buf)
{
    win_T	*wp;
    int		other_buffer = FALSE;
    int		close_curwin = FALSE;
    int		dir;
    int		help_window = FALSE;
    tabpage_T   *prev_curtab = curtab;
    frame_T	*win_frame = win->w_frame->fr_parent;
#ifdef FEAT_DIFF
    int		had_diffmode = win->w_p_diff;
#endif
#ifdef MESSAGE_QUEUE
    int		did_decrement = FALSE;
#endif

#if defined(FEAT_TERMINAL) && defined(FEAT_PROP_POPUP)
    // Can close a popup window with a terminal if the job has finished.
    if (may_close_term_popup() == OK)
	return OK;
#endif
    if (ERROR_IF_ANY_POPUP_WINDOW)
	return FAIL;

    if (last_window())
    {
	emsg(_(e_cannot_close_last_window));
	return FAIL;
    }
    if (window_layout_locked(CMD_close))
	return FAIL;

    if (win->w_closing || (win->w_buffer != NULL
					       && win->w_buffer->b_locked > 0))
	return FAIL; // window is already being closed
    if (win_unlisted(win))
    {
	emsg(_(e_cannot_close_autocmd_or_popup_window));
	return FAIL;
    }
    if ((is_aucmd_win(firstwin) || is_aucmd_win(lastwin)) && one_window())
    {
	emsg(_(e_cannot_close_window_only_autocmd_window_would_remain));
	return FAIL;
    }

    // When closing the last window in a tab page first go to another tab page
    // and then close the window and the tab page to avoid that curwin and
    // curtab are invalid while we are freeing memory.
    if (close_last_window_tabpage(win, free_buf, prev_curtab))
      return FAIL;

    // When closing the help window, try restoring a snapshot after closing
    // the window.  Otherwise clear the snapshot, it's now invalid.
    if (bt_help(win->w_buffer))
	help_window = TRUE;
    else
	clear_snapshot(curtab, SNAP_HELP_IDX);

    if (win == curwin)
    {
#ifdef FEAT_JOB_CHANNEL
	leaving_window(curwin);
#endif
	/*
	 * Guess which window is going to be the new current window.
	 * This may change because of the autocommands (sigh).
	 */
	wp = frame2win(win_altframe(win, NULL));

	/*
	 * Be careful: If autocommands delete the window or cause this window
	 * to be the last one left, return now.
	 */
	if (wp->w_buffer != curbuf)
	{
	    reset_VIsual_and_resel();	// stop Visual mode

	    other_buffer = TRUE;
	    win->w_closing = TRUE;
	    apply_autocmds(EVENT_BUFLEAVE, NULL, NULL, FALSE, curbuf);
	    if (!win_valid(win))
		return FAIL;
	    win->w_closing = FALSE;
	    if (last_window())
		return FAIL;
	}
	win->w_closing = TRUE;
	apply_autocmds(EVENT_WINLEAVE, NULL, NULL, FALSE, curbuf);
	if (!win_valid(win))
	    return FAIL;
	win->w_closing = FALSE;
	if (last_window())
	    return FAIL;
#ifdef FEAT_EVAL
	// autocmds may abort script processing
	if (aborting())
	    return FAIL;
#endif
    }

#ifdef FEAT_GUI
    // Avoid trouble with scrollbars that are going to be deleted in
    // win_free().
    if (gui.in_use)
	out_flush();
#endif

#ifdef FEAT_PROP_POPUP
    if (popup_win_closed(win) && !win_valid(win))
	return FAIL;
#endif

    // Trigger WinClosed just before starting to free window-related resources.
    trigger_winclosed(win);
    // autocmd may have freed the window already.
    if (!win_valid_any_tab(win))
	return OK;

    win_close_buffer(win, free_buf ? DOBUF_UNLOAD : 0, TRUE);

    if (only_one_window() && win_valid(win) && win->w_buffer == NULL
	    && (last_window() || curtab != prev_curtab
		|| close_last_window_tabpage(win, free_buf, prev_curtab)))
    {
	// Autocommands have closed all windows, quit now.  Restore
	// curwin->w_buffer, otherwise writing viminfo may fail.
	if (curwin->w_buffer == NULL)
	    curwin->w_buffer = curbuf;
	getout(0);
    }

    // Autocommands may have moved to another tab page.
    if (curtab != prev_curtab && win_valid_any_tab(win)
						      && win->w_buffer == NULL)
    {
	// Need to close the window anyway, since the buffer is NULL.
	// Don't trigger autocmds with a NULL buffer.
	block_autocmds();
	win_close_othertab(win, FALSE, prev_curtab);
	unblock_autocmds();
	return FAIL;
    }

    // Autocommands may have closed the window already or closed the only
    // other window.
    if (!win_valid(win) || last_window()
	    || close_last_window_tabpage(win, free_buf, prev_curtab))
	return FAIL;

    // Now we are really going to close the window.  Disallow any autocommand
    // to split a window to avoid trouble.
    // Also bail out of parse_queued_messages() to avoid it tries to update the
    // screen.
    ++split_disallowed;
#ifdef MESSAGE_QUEUE
    ++dont_parse_messages;
#endif

    // Free the memory used for the window and get the window that received
    // the screen space.
    wp = win_free_mem(win, &dir, NULL);

    if (help_window)
    {
	// Closing the help window moves the cursor back to the current window
	// of the snapshot.
	win_T *prev_win = get_snapshot_curwin(SNAP_HELP_IDX);

	if (win_valid(prev_win))
	    wp = prev_win;
    }

    // Make sure curwin isn't invalid.  It can cause severe trouble when
    // printing an error message.  For win_equal() curbuf needs to be valid
    // too.
    if (win == curwin)
    {
	curwin = wp;
#ifdef FEAT_QUICKFIX
	if (wp->w_p_pvw || bt_quickfix(wp->w_buffer))
	{
	    /*
	     * If the cursor goes to the preview or the quickfix window, try
	     * finding another window to go to.
	     */
	    for (;;)
	    {
		if (wp->w_next == NULL)
		    wp = firstwin;
		else
		    wp = wp->w_next;
		if (wp == curwin)
		    break;
		if (!wp->w_p_pvw && !bt_quickfix(wp->w_buffer))
		{
		    curwin = wp;
		    break;
		}
	    }
	}
#endif
	curbuf = curwin->w_buffer;
	close_curwin = TRUE;

	// The cursor position may be invalid if the buffer changed after last
	// using the window.
	check_cursor();
    }

    /*
     * If last window has a status line now and we don't want one, remove the
     * status line.  Do this before win_equal(), because it may change the
     * height of a window
     */
    last_status(FALSE);

    if (p_ea && (*p_ead == 'b' || *p_ead == dir))
	// If the frame of the closed window contains the new current window,
	// only resize that frame.  Otherwise resize all windows.
	win_equal(curwin, curwin->w_frame->fr_parent == win_frame, dir);
    else
    {
	win_comp_pos();
	win_fix_scroll(FALSE);
    }
    if (close_curwin)
    {
	// Pass WEE_ALLOW_PARSE_MESSAGES to decrement dont_parse_messages
	// before autocommands.
#ifdef MESSAGE_QUEUE
	did_decrement =
#else
	(void)
#endif
	    win_enter_ext(wp,
		WEE_CURWIN_INVALID | WEE_TRIGGER_ENTER_AUTOCMDS
		      | WEE_TRIGGER_LEAVE_AUTOCMDS | WEE_ALLOW_PARSE_MESSAGES);
	if (other_buffer)
	    // careful: after this wp and win may be invalid!
	    apply_autocmds(EVENT_BUFENTER, NULL, NULL, FALSE, curbuf);
    }

    --split_disallowed;
#ifdef MESSAGE_QUEUE
    if (!did_decrement)
	--dont_parse_messages;
#endif

    // After closing the help window, try restoring the window layout from
    // before it was opened.
    if (help_window)
	restore_snapshot(SNAP_HELP_IDX, close_curwin);

#ifdef FEAT_DIFF
    // If the window had 'diff' set and now there is only one window left in
    // the tab page with 'diff' set, and "closeoff" is in 'diffopt', then
    // execute ":diffoff!".
    if (diffopt_closeoff() && had_diffmode && curtab == prev_curtab)
    {
	int	diffcount = 0;
	win_T	*dwin;

	FOR_ALL_WINDOWS(dwin)
	    if (dwin->w_p_diff)
		++diffcount;
	if (diffcount == 1)
	    do_cmdline_cmd((char_u *)"diffoff!");
    }
#endif

#if defined(FEAT_GUI)
    // When 'guioptions' includes 'L' or 'R' may have to remove scrollbars.
    if (gui.in_use && !win_hasvertsplit())
	gui_init_which_components(NULL);
#endif

    redraw_all_later(UPD_NOT_VALID);
    return OK;
}

    static void
trigger_winclosed(win_T *win)
{
    static int	recursive = FALSE;
    char_u	winid[NUMBUFLEN];

    if (recursive)
	return;
    recursive = TRUE;
    vim_snprintf((char *)winid, sizeof(winid), "%d", win->w_id);
    apply_autocmds(EVENT_WINCLOSED, winid, winid, FALSE, win->w_buffer);
    recursive = FALSE;
}

/*
 * Make a snapshot of all the window scroll positions and sizes of the current
 * tab page.
 */
    void
snapshot_windows_scroll_size(void)
{
    win_T *wp;
    FOR_ALL_WINDOWS(wp)
    {
	wp->w_last_topline = wp->w_topline;
#ifdef FEAT_DIFF
	wp->w_last_topfill = wp->w_topfill;
#endif
	wp->w_last_leftcol = wp->w_leftcol;
	wp->w_last_skipcol = wp->w_skipcol;
	wp->w_last_width = wp->w_width;
	wp->w_last_height = wp->w_height;
    }
}

static int did_initial_scroll_size_snapshot = FALSE;

    void
may_make_initial_scroll_size_snapshot(void)
{
    if (!did_initial_scroll_size_snapshot)
    {
	did_initial_scroll_size_snapshot = TRUE;
	snapshot_windows_scroll_size();
    }
}

#ifdef FEAT_EVAL
/*
 * Create a dictionary with information about size and scroll changes in a
 * window.
 * Returns the dictionary with refcount set to one.
 * Returns NULL when out of memory.
 */
    static dict_T *
make_win_info_dict(
	int width,
	int height,
	int topline,
# ifdef FEAT_DIFF
	int topfill,
# endif
	int leftcol,
	int skipcol)
{
    dict_T *d = dict_alloc();
    if (d == NULL)
	return NULL;
    d->dv_refcount = 1;

    // not actually looping, for breaking out on error
    while (1)
    {
	typval_T tv;
	tv.v_lock = 0;
	tv.v_type = VAR_NUMBER;

	tv.vval.v_number = width;
	if (dict_add_tv(d, "width", &tv) == FAIL)
	    break;
	tv.vval.v_number = height;
	if (dict_add_tv(d, "height", &tv) == FAIL)
	    break;
	tv.vval.v_number = topline;
	if (dict_add_tv(d, "topline", &tv) == FAIL)
	    break;
#ifdef FEAT_DIFF
	tv.vval.v_number = topfill;
#else
	tv.vval.v_number = 0;
#endif
	if (dict_add_tv(d, "topfill", &tv) == FAIL)
	    break;
	tv.vval.v_number = leftcol;
	if (dict_add_tv(d, "leftcol", &tv) == FAIL)
	    break;
	tv.vval.v_number = skipcol;
	if (dict_add_tv(d, "skipcol", &tv) == FAIL)
	    break;
	return d;
    }
    dict_unref(d);
    return NULL;
}
#endif

// Return values of check_window_scroll_resize():
#define CWSR_SCROLLED	1  // at least one window scrolled
#define CWSR_RESIZED	2  // at least one window size changed

/*
 * This function is used for three purposes:
 * 1. Goes over all windows in the current tab page and returns:
 *	0				no scrolling and no size changes found
 *	CWSR_SCROLLED			at least one window scrolled
 *	CWSR_RESIZED			at least one window changed size
 *	CWSR_SCROLLED + CWSR_RESIZED	both
 *    "size_count" is set to the nr of windows with size changes.
 *    "first_scroll_win" is set to the first window with any relevant changes.
 *    "first_size_win" is set to the first window with size changes.
 *
 * 2. When the first three arguments are NULL and "winlist" is not NULL,
 *    "winlist" is set to the list of window IDs with size changes.
 *
 * 3. When the first three arguments are NULL and "v_event" is not NULL,
 *    information about changed windows is added to "v_event".
 */
    static int
check_window_scroll_resize(
	int	*size_count,
	win_T	**first_scroll_win,
	win_T	**first_size_win,
	list_T	*winlist UNUSED,
	dict_T	*v_event UNUSED)
{
    int result = 0;
#ifdef FEAT_EVAL
    int listidx = 0;
    int tot_width = 0;
    int tot_height = 0;
    int tot_topline = 0;
# ifdef FEAT_DIFF
    int tot_topfill = 0;
# endif
    int tot_leftcol = 0;
    int tot_skipcol = 0;
#endif

    win_T *wp;
    FOR_ALL_WINDOWS(wp)
    {
	int size_changed = wp->w_last_width != wp->w_width
					  || wp->w_last_height != wp->w_height;
	if (size_changed)
	{
	    result |= CWSR_RESIZED;
#ifdef FEAT_EVAL
	    if (winlist != NULL)
	    {
		// Add this window to the list of changed windows.
		typval_T tv;
		tv.v_lock = 0;
		tv.v_type = VAR_NUMBER;
		tv.vval.v_number = wp->w_id;
		list_set_item(winlist, listidx++, &tv);
	    }
	    else
#endif
		if (size_count != NULL)
	    {
		++*size_count;
		if (*first_size_win == NULL)
		    *first_size_win = wp;
		// For WinScrolled the first window with a size change is used
		// even when it didn't scroll.
		if (*first_scroll_win == NULL)
		    *first_scroll_win = wp;
	    }
	}

	int scroll_changed = wp->w_last_topline != wp->w_topline
#ifdef FEAT_DIFF
				|| wp->w_last_topfill != wp->w_topfill
#endif
				|| wp->w_last_leftcol != wp->w_leftcol
				|| wp->w_last_skipcol != wp->w_skipcol;
	if (scroll_changed)
	{
	    result |= CWSR_SCROLLED;
	    if (first_scroll_win != NULL && *first_scroll_win == NULL)
		*first_scroll_win = wp;
	}

#ifdef FEAT_EVAL
	if ((size_changed || scroll_changed) && v_event != NULL)
	{
	    // Add info about this window to the v:event dictionary.
	    int width = wp->w_width - wp->w_last_width;
	    int height = wp->w_height - wp->w_last_height;
	    int topline = wp->w_topline - wp->w_last_topline;
#ifdef FEAT_DIFF
	    int topfill = wp->w_topfill - wp->w_last_topfill;
#endif
	    int leftcol = wp->w_leftcol - wp->w_last_leftcol;
	    int skipcol = wp->w_skipcol - wp->w_last_skipcol;
	    dict_T *d = make_win_info_dict(width, height, topline,
#ifdef FEAT_DIFF
							    topfill,
#endif
							    leftcol, skipcol);
	    if (d == NULL)
		break;
	    char winid[NUMBUFLEN];
	    vim_snprintf(winid, sizeof(winid), "%d", wp->w_id);
	    if (dict_add_dict(v_event, winid, d) == FAIL)
	    {
		dict_unref(d);
		break;
	    }
	    --d->dv_refcount;

	    tot_width += abs(width);
	    tot_height += abs(height);
	    tot_topline += abs(topline);
#ifdef FEAT_DIFF
	    tot_topfill += abs(topfill);
#endif
	    tot_leftcol += abs(leftcol);
	    tot_skipcol += abs(skipcol);
	}
#endif
    }

#ifdef FEAT_EVAL
    if (v_event != NULL)
    {
	dict_T *alldict = make_win_info_dict(tot_width, tot_height, tot_topline,
# ifdef FEAT_DIFF
						    tot_topfill,
# endif
						    tot_leftcol, tot_skipcol);
	if (alldict != NULL)
	{
	    if (dict_add_dict(v_event, "all", alldict) == FAIL)
		dict_unref(alldict);
	    else
		--alldict->dv_refcount;
	}
    }
#endif

    return result;
}

/*
 * Trigger WinScrolled and/or WinResized if any window in the current tab page
 * scrolled or changed size.
 */
    void
may_trigger_win_scrolled_resized(void)
{
    static int	    recursive = FALSE;
    int		    do_resize = has_winresized();
    int		    do_scroll = has_winscrolled();

    // Do not trigger WinScrolled or WinResized recursively.  Do not trigger
    // before the initial snapshot of the w_last_ values was made.
    if (recursive
	    || !(do_scroll || do_resize)
	    || !did_initial_scroll_size_snapshot)
	return;

    int size_count = 0;
    win_T *first_scroll_win = NULL, *first_size_win = NULL;
    int cwsr = check_window_scroll_resize(&size_count,
					   &first_scroll_win, &first_size_win,
					   NULL, NULL);
    int trigger_resize = do_resize && size_count > 0;
    int trigger_scroll = do_scroll && cwsr != 0;
    if (!trigger_resize && !trigger_scroll)
	return;  // no relevant changes
#ifdef FEAT_EVAL
    list_T *windows_list = NULL;
    if (trigger_resize)
    {
	// Create the list for v:event.windows before making the snapshot.
	windows_list = list_alloc_with_items(size_count);
	(void)check_window_scroll_resize(NULL, NULL, NULL, windows_list, NULL);
    }

    dict_T *scroll_dict = NULL;
    if (trigger_scroll)
    {
	// Create the dict with entries for v:event before making the snapshot.
	scroll_dict = dict_alloc();
	if (scroll_dict != NULL)
	{
	    scroll_dict->dv_refcount = 1;
	    (void)check_window_scroll_resize(NULL, NULL, NULL, NULL,
								  scroll_dict);
	}
    }
#endif

    // WinScrolled/WinResized are triggered only once, even when multiple
    // windows scrolled or changed size.  Store the current values before
    // triggering the event, if a scroll or resize happens as a side effect
    // then WinScrolled/WinResized is triggered for that later.
    snapshot_windows_scroll_size();

    // "curwin" may be different from the actual current window, make
    // sure it can be restored.
    window_layout_lock();
    recursive = TRUE;

    // If both are to be triggered do WinResized first.
    if (trigger_resize)
    {
#ifdef FEAT_EVAL
	save_v_event_T  save_v_event;
	dict_T		*v_event = get_v_event(&save_v_event);

	if (dict_add_list(v_event, "windows", windows_list) == OK)
	{
	    dict_set_items_ro(v_event);
#endif
	    char_u winid[NUMBUFLEN];
	    vim_snprintf((char *)winid, sizeof(winid), "%d",
							 first_size_win->w_id);
	    apply_autocmds(EVENT_WINRESIZED, winid, winid, FALSE,
						     first_size_win->w_buffer);
#ifdef FEAT_EVAL
	}
	restore_v_event(v_event, &save_v_event);
#endif
    }

    if (trigger_scroll
#ifdef FEAT_EVAL
	    && scroll_dict != NULL
#endif
	    )
    {
#ifdef FEAT_EVAL
	save_v_event_T  save_v_event;
	dict_T		*v_event = get_v_event(&save_v_event);

	// Move the entries from scroll_dict to v_event.
	dict_extend(v_event, scroll_dict, (char_u *)"move", NULL);
	dict_set_items_ro(v_event);
	dict_unref(scroll_dict);
#endif
	char_u winid[NUMBUFLEN];
	vim_snprintf((char *)winid, sizeof(winid), "%d",
						       first_scroll_win->w_id);
	apply_autocmds(EVENT_WINSCROLLED, winid, winid, FALSE,
						   first_scroll_win->w_buffer);
#ifdef FEAT_EVAL
	restore_v_event(v_event, &save_v_event);
#endif
    }

    recursive = FALSE;
    window_layout_unlock();
}

/*
 * Close window "win" in tab page "tp", which is not the current tab page.
 * This may be the last window in that tab page and result in closing the tab,
 * thus "tp" may become invalid!
 * Caller must check if buffer is hidden and whether the tabline needs to be
 * updated.
 */
    void
win_close_othertab(win_T *win, int free_buf, tabpage_T *tp)
{
    win_T	*wp;
    int		dir;
    tabpage_T   *ptp = NULL;
    int		free_tp = FALSE;

    // Get here with win->w_buffer == NULL when win_close() detects the tab
    // page changed.
    if (win->w_closing || (win->w_buffer != NULL
					       && win->w_buffer->b_locked > 0))
	return; // window is already being closed

    // Trigger WinClosed just before starting to free window-related resources.
    trigger_winclosed(win);
    // autocmd may have freed the window already.
    if (!win_valid_any_tab(win))
	return;

    if (win->w_buffer != NULL)
	// Close the link to the buffer.
	close_buffer(win, win->w_buffer, free_buf ? DOBUF_UNLOAD : 0,
								 FALSE, TRUE);

    // Careful: Autocommands may have closed the tab page or made it the
    // current tab page.
    for (ptp = first_tabpage; ptp != NULL && ptp != tp; ptp = ptp->tp_next)
	;
    if (ptp == NULL || tp == curtab)
    {
	// If the buffer was removed from the window we have to give it any
	// buffer.
	if (win_valid_any_tab(win) && win->w_buffer == NULL)
	{
	    win->w_buffer = firstbuf;
	    ++firstbuf->b_nwindows;
	    win_init_empty(win);
	}
	return;
    }

    // Autocommands may have closed the window already.
    for (wp = tp->tp_firstwin; wp != NULL && wp != win; wp = wp->w_next)
	;
    if (wp == NULL)
	return;

    // When closing the last window in a tab page remove the tab page.
    if (tp->tp_firstwin == tp->tp_lastwin)
    {
	int	h = tabline_height();

	if (tp == first_tabpage)
	    first_tabpage = tp->tp_next;
	else
	{
	    for (ptp = first_tabpage; ptp != NULL && ptp->tp_next != tp;
							   ptp = ptp->tp_next)
		;
	    if (ptp == NULL)
	    {
		internal_error("win_close_othertab()");
		return;
	    }
	    ptp->tp_next = tp->tp_next;
	}
	free_tp = TRUE;
	redraw_tabline = TRUE;
	if (h != tabline_height())
	    shell_new_rows();
    }

    // Free the memory used for the window.
    win_free_mem(win, &dir, tp);

    if (free_tp)
	free_tabpage(tp);
}

/*
 * Free the memory used for a window.
 * Returns a pointer to the window that got the freed up space.
 */
    static win_T *
win_free_mem(
    win_T	*win,
    int		*dirp,		// set to 'v' or 'h' for direction if 'ea'
    tabpage_T	*tp)		// tab page "win" is in, NULL for current
{
    frame_T	*frp;
    win_T	*wp;
    tabpage_T	*win_tp = tp == NULL ? curtab : tp;

    // Remove the window and its frame from the tree of frames.
    frp = win->w_frame;
    wp = winframe_remove(win, dirp, tp);
    vim_free(frp);
    win_free(win, tp);

    // When deleting the current window in the tab, select a new current
    // window.
    if (win == win_tp->tp_curwin)
	win_tp->tp_curwin = wp;

    return wp;
}

#if defined(EXITFREE) || defined(PROTO)
    void
win_free_all(void)
{
    int		dummy;

    // avoid an error for switching tabpage with the cmdline window open
    cmdwin_type = 0;

    while (first_tabpage->tp_next != NULL)
	tabpage_close(TRUE);

    for (int i = 0; i < AUCMD_WIN_COUNT; ++i)
	if (aucmd_win[i].auc_win != NULL)
	{
	    (void)win_free_mem(aucmd_win[i].auc_win, &dummy, NULL);
	    aucmd_win[i].auc_win = NULL;
	}

    while (firstwin != NULL)
	(void)win_free_mem(firstwin, &dummy, NULL);

    // No window should be used after this. Set curwin to NULL to crash
    // instead of using freed memory.
    curwin = NULL;
}
#endif

/*
 * Remove a window and its frame from the tree of frames.
 * Returns a pointer to the window that got the freed up space.
 */
    win_T *
winframe_remove(
    win_T	*win,
    int		*dirp UNUSED,	// set to 'v' or 'h' for direction if 'ea'
    tabpage_T	*tp)		// tab page "win" is in, NULL for current
{
    frame_T	*frp, *frp2, *frp3;
    frame_T	*frp_close = win->w_frame;
    win_T	*wp;

    /*
     * If there is only one window there is nothing to remove.
     */
    if (tp == NULL ? ONE_WINDOW : tp->tp_firstwin == tp->tp_lastwin)
	return NULL;

    /*
     * Remove the window from its frame.
     */
    frp2 = win_altframe(win, tp);
    wp = frame2win(frp2);

    // Remove this frame from the list of frames.
    frame_remove(frp_close);

    if (frp_close->fr_parent->fr_layout == FR_COL)
    {
	// When 'winfixheight' is set, try to find another frame in the column
	// (as close to the closed frame as possible) to distribute the height
	// to.
	if (frp2->fr_win != NULL && frp2->fr_win->w_p_wfh)
	{
	    frp = frp_close->fr_prev;
	    frp3 = frp_close->fr_next;
	    while (frp != NULL || frp3 != NULL)
	    {
		if (frp != NULL)
		{
		    if (!frame_fixed_height(frp))
		    {
			frp2 = frp;
			wp = frame2win(frp2);
			break;
		    }
		    frp = frp->fr_prev;
		}
		if (frp3 != NULL)
		{
		    if (frp3->fr_win != NULL && !frp3->fr_win->w_p_wfh)
		    {
			frp2 = frp3;
			wp = frp3->fr_win;
			break;
		    }
		    frp3 = frp3->fr_next;
		}
	    }
	}
	frame_new_height(frp2, frp2->fr_height + frp_close->fr_height,
			    frp2 == frp_close->fr_next ? TRUE : FALSE, FALSE);
	*dirp = 'v';
    }
    else
    {
	// When 'winfixwidth' is set, try to find another frame in the column
	// (as close to the closed frame as possible) to distribute the width
	// to.
	if (frp2->fr_win != NULL && frp2->fr_win->w_p_wfw)
	{
	    frp = frp_close->fr_prev;
	    frp3 = frp_close->fr_next;
	    while (frp != NULL || frp3 != NULL)
	    {
		if (frp != NULL)
		{
		    if (!frame_fixed_width(frp))
		    {
			frp2 = frp;
			wp = frame2win(frp2);
			break;
		    }
		    frp = frp->fr_prev;
		}
		if (frp3 != NULL)
		{
		    if (frp3->fr_win != NULL && !frp3->fr_win->w_p_wfw)
		    {
			frp2 = frp3;
			wp = frp3->fr_win;
			break;
		    }
		    frp3 = frp3->fr_next;
		}
	    }
	}
	frame_new_width(frp2, frp2->fr_width + frp_close->fr_width,
			    frp2 == frp_close->fr_next ? TRUE : FALSE, FALSE);
	*dirp = 'h';
    }

    // If rows/columns go to a window below/right its positions need to be
    // updated.  Can only be done after the sizes have been updated.
    if (frp2 == frp_close->fr_next)
    {
	int row = win->w_winrow;
	int col = win->w_wincol;

	frame_comp_pos(frp2, &row, &col);
    }

    if (frp2->fr_next == NULL && frp2->fr_prev == NULL)
    {
	// There is no other frame in this list, move its info to the parent
	// and remove it.
	frp2->fr_parent->fr_layout = frp2->fr_layout;
	frp2->fr_parent->fr_child = frp2->fr_child;
	FOR_ALL_FRAMES(frp, frp2->fr_child)
	    frp->fr_parent = frp2->fr_parent;
	frp2->fr_parent->fr_win = frp2->fr_win;
	if (frp2->fr_win != NULL)
	    frp2->fr_win->w_frame = frp2->fr_parent;
	frp = frp2->fr_parent;
	if (topframe->fr_child == frp2)
	    topframe->fr_child = frp;
	vim_free(frp2);

	frp2 = frp->fr_parent;
	if (frp2 != NULL && frp2->fr_layout == frp->fr_layout)
	{
	    // The frame above the parent has the same layout, have to merge
	    // the frames into this list.
	    if (frp2->fr_child == frp)
		frp2->fr_child = frp->fr_child;
	    frp->fr_child->fr_prev = frp->fr_prev;
	    if (frp->fr_prev != NULL)
		frp->fr_prev->fr_next = frp->fr_child;
	    for (frp3 = frp->fr_child; ; frp3 = frp3->fr_next)
	    {
		frp3->fr_parent = frp2;
		if (frp3->fr_next == NULL)
		{
		    frp3->fr_next = frp->fr_next;
		    if (frp->fr_next != NULL)
			frp->fr_next->fr_prev = frp3;
		    break;
		}
	    }
	    if (topframe->fr_child == frp)
		topframe->fr_child = frp2;
	    vim_free(frp);
	}
    }

    return wp;
}

/*
 * Return a pointer to the frame that will receive the empty screen space that
 * is left over after "win" is closed.
 *
 * If 'splitbelow' or 'splitright' is set, the space goes above or to the left
 * by default.  Otherwise, the free space goes below or to the right.  The
 * result is that opening a window and then immediately closing it will
 * preserve the initial window layout.  The 'wfh' and 'wfw' settings are
 * respected when possible.
 */
    static frame_T *
win_altframe(
    win_T	*win,
    tabpage_T	*tp)		// tab page "win" is in, NULL for current
{
    frame_T	*frp;
    frame_T	*other_fr, *target_fr;

    if (tp == NULL ? ONE_WINDOW : tp->tp_firstwin == tp->tp_lastwin)
	return alt_tabpage()->tp_curwin->w_frame;

    frp = win->w_frame;

    if (frp->fr_prev == NULL)
	return frp->fr_next;
    if (frp->fr_next == NULL)
	return frp->fr_prev;

    // By default the next window will get the space that was abandoned by this
    // window
    target_fr = frp->fr_next;
    other_fr  = frp->fr_prev;

    // If this is part of a column of windows and 'splitbelow' is true then the
    // previous window will get the space.
    if (frp->fr_parent != NULL && frp->fr_parent->fr_layout == FR_COL && p_sb)
    {
	target_fr = frp->fr_prev;
	other_fr  = frp->fr_next;
    }

    // If this is part of a row of windows, and 'splitright' is true then the
    // previous window will get the space.
    if (frp->fr_parent != NULL && frp->fr_parent->fr_layout == FR_ROW && p_spr)
    {
	target_fr = frp->fr_prev;
	other_fr  = frp->fr_next;
    }

    // If 'wfh' or 'wfw' is set for the target and not for the alternate
    // window, reverse the selection.
    if (frp->fr_parent != NULL && frp->fr_parent->fr_layout == FR_ROW)
    {
	if (frame_fixed_width(target_fr) && !frame_fixed_width(other_fr))
	    target_fr = other_fr;
    }
    else
    {
	if (frame_fixed_height(target_fr) && !frame_fixed_height(other_fr))
	    target_fr = other_fr;
    }

    return target_fr;
}

/*
 * Return the tabpage that will be used if the current one is closed.
 */
    static tabpage_T *
alt_tabpage(void)
{
    tabpage_T	*tp;

    // Use the next tab page if possible.
    if (curtab->tp_next != NULL)
	return curtab->tp_next;

    // Find the last but one tab page.
    for (tp = first_tabpage; tp->tp_next != curtab; tp = tp->tp_next)
	;
    return tp;
}

/*
 * Find the left-upper window in frame "frp".
 */
    static win_T *
frame2win(frame_T *frp)
{
    while (frp->fr_win == NULL)
	frp = frp->fr_child;
    return frp->fr_win;
}

/*
 * Return TRUE if frame "frp" contains window "wp".
 */
    static int
frame_has_win(frame_T *frp, win_T *wp)
{
    frame_T	*p;

    if (frp->fr_layout == FR_LEAF)
	return frp->fr_win == wp;

    FOR_ALL_FRAMES(p, frp->fr_child)
	if (frame_has_win(p, wp))
	    return TRUE;
    return FALSE;
}

/*
 * Set a new height for a frame.  Recursively sets the height for contained
 * frames and windows.  Caller must take care of positions.
 */
    static void
frame_new_height(
    frame_T	*topfrp,
    int		height,
    int		topfirst,	// resize topmost contained frame first
    int		wfh)		// obey 'winfixheight' when there is a choice;
				// may cause the height not to be set
{
    frame_T	*frp;
    int		extra_lines;
    int		h;

    if (topfrp->fr_win != NULL)
    {
	// Simple case: just one window.
	win_new_height(topfrp->fr_win,
				    height - topfrp->fr_win->w_status_height
					      - WINBAR_HEIGHT(topfrp->fr_win));
    }
    else if (topfrp->fr_layout == FR_ROW)
    {
	do
	{
	    // All frames in this row get the same new height.
	    FOR_ALL_FRAMES(frp, topfrp->fr_child)
	    {
		frame_new_height(frp, height, topfirst, wfh);
		if (frp->fr_height > height)
		{
		    // Could not fit the windows, make the whole row higher.
		    height = frp->fr_height;
		    break;
		}
	    }
	}
	while (frp != NULL);
    }
    else    // fr_layout == FR_COL
    {
	// Complicated case: Resize a column of frames.  Resize the bottom
	// frame first, frames above that when needed.

	frp = topfrp->fr_child;
	if (wfh)
	    // Advance past frames with one window with 'wfh' set.
	    while (frame_fixed_height(frp))
	    {
		frp = frp->fr_next;
		if (frp == NULL)
		    return;	    // no frame without 'wfh', give up
	    }
	if (!topfirst)
	{
	    // Find the bottom frame of this column
	    while (frp->fr_next != NULL)
		frp = frp->fr_next;
	    if (wfh)
		// Advance back for frames with one window with 'wfh' set.
		while (frame_fixed_height(frp))
		    frp = frp->fr_prev;
	}

	extra_lines = height - topfrp->fr_height;
	if (extra_lines < 0)
	{
	    // reduce height of contained frames, bottom or top frame first
	    while (frp != NULL)
	    {
		h = frame_minheight(frp, NULL);
		if (frp->fr_height + extra_lines < h)
		{
		    extra_lines += frp->fr_height - h;
		    frame_new_height(frp, h, topfirst, wfh);
		}
		else
		{
		    frame_new_height(frp, frp->fr_height + extra_lines,
							       topfirst, wfh);
		    break;
		}
		if (topfirst)
		{
		    do
			frp = frp->fr_next;
		    while (wfh && frp != NULL && frame_fixed_height(frp));
		}
		else
		{
		    do
			frp = frp->fr_prev;
		    while (wfh && frp != NULL && frame_fixed_height(frp));
		}
		// Increase "height" if we could not reduce enough frames.
		if (frp == NULL)
		    height -= extra_lines;
	    }
	}
	else if (extra_lines > 0)
	{
	    // increase height of bottom or top frame
	    frame_new_height(frp, frp->fr_height + extra_lines, topfirst, wfh);
	}
    }
    topfrp->fr_height = height;
}

/*
 * Return TRUE if height of frame "frp" should not be changed because of
 * the 'winfixheight' option.
 */
    static int
frame_fixed_height(frame_T *frp)
{
    // frame with one window: fixed height if 'winfixheight' set.
    if (frp->fr_win != NULL)
	return frp->fr_win->w_p_wfh;

    if (frp->fr_layout == FR_ROW)
    {
	// The frame is fixed height if one of the frames in the row is fixed
	// height.
	FOR_ALL_FRAMES(frp, frp->fr_child)
	    if (frame_fixed_height(frp))
		return TRUE;
	return FALSE;
    }

    // frp->fr_layout == FR_COL: The frame is fixed height if all of the
    // frames in the row are fixed height.
    FOR_ALL_FRAMES(frp, frp->fr_child)
	if (!frame_fixed_height(frp))
	    return FALSE;
    return TRUE;
}

/*
 * Return TRUE if width of frame "frp" should not be changed because of
 * the 'winfixwidth' option.
 */
    static int
frame_fixed_width(frame_T *frp)
{
    // frame with one window: fixed width if 'winfixwidth' set.
    if (frp->fr_win != NULL)
	return frp->fr_win->w_p_wfw;

    if (frp->fr_layout == FR_COL)
    {
	// The frame is fixed width if one of the frames in the row is fixed
	// width.
	FOR_ALL_FRAMES(frp, frp->fr_child)
	    if (frame_fixed_width(frp))
		return TRUE;
	return FALSE;
    }

    // frp->fr_layout == FR_ROW: The frame is fixed width if all of the
    // frames in the row are fixed width.
    FOR_ALL_FRAMES(frp, frp->fr_child)
	if (!frame_fixed_width(frp))
	    return FALSE;
    return TRUE;
}

/*
 * Add a status line to windows at the bottom of "frp".
 * Note: Does not check if there is room!
 */
    static void
frame_add_statusline(frame_T *frp)
{
    win_T	*wp;

    if (frp->fr_layout == FR_LEAF)
    {
	wp = frp->fr_win;
	wp->w_status_height = STATUS_HEIGHT;
    }
    else if (frp->fr_layout == FR_ROW)
    {
	// Handle all the frames in the row.
	FOR_ALL_FRAMES(frp, frp->fr_child)
	    frame_add_statusline(frp);
    }
    else // frp->fr_layout == FR_COL
    {
	// Only need to handle the last frame in the column.
	for (frp = frp->fr_child; frp->fr_next != NULL; frp = frp->fr_next)
	    ;
	frame_add_statusline(frp);
    }
}

/*
 * Set width of a frame.  Handles recursively going through contained frames.
 * May remove separator line for windows at the right side (for win_close()).
 */
    static void
frame_new_width(
    frame_T	*topfrp,
    int		width,
    int		leftfirst,	// resize leftmost contained frame first
    int		wfw)		// obey 'winfixwidth' when there is a choice;
				// may cause the width not to be set
{
    frame_T	*frp;
    int		extra_cols;
    int		w;
    win_T	*wp;

    if (topfrp->fr_layout == FR_LEAF)
    {
	// Simple case: just one window.
	wp = topfrp->fr_win;
	// Find out if there are any windows right of this one.
	for (frp = topfrp; frp->fr_parent != NULL; frp = frp->fr_parent)
	    if (frp->fr_parent->fr_layout == FR_ROW && frp->fr_next != NULL)
		break;
	if (frp->fr_parent == NULL)
	    wp->w_vsep_width = 0;
	win_new_width(wp, width - wp->w_vsep_width);
    }
    else if (topfrp->fr_layout == FR_COL)
    {
	do
	{
	    // All frames in this column get the same new width.
	    FOR_ALL_FRAMES(frp, topfrp->fr_child)
	    {
		frame_new_width(frp, width, leftfirst, wfw);
		if (frp->fr_width > width)
		{
		    // Could not fit the windows, make whole column wider.
		    width = frp->fr_width;
		    break;
		}
	    }
	} while (frp != NULL);
    }
    else    // fr_layout == FR_ROW
    {
	// Complicated case: Resize a row of frames.  Resize the rightmost
	// frame first, frames left of it when needed.

	frp = topfrp->fr_child;
	if (wfw)
	    // Advance past frames with one window with 'wfw' set.
	    while (frame_fixed_width(frp))
	    {
		frp = frp->fr_next;
		if (frp == NULL)
		    return;	    // no frame without 'wfw', give up
	    }
	if (!leftfirst)
	{
	    // Find the rightmost frame of this row
	    while (frp->fr_next != NULL)
		frp = frp->fr_next;
	    if (wfw)
		// Advance back for frames with one window with 'wfw' set.
		while (frame_fixed_width(frp))
		    frp = frp->fr_prev;
	}

	extra_cols = width - topfrp->fr_width;
	if (extra_cols < 0)
	{
	    // reduce frame width, rightmost frame first
	    while (frp != NULL)
	    {
		w = frame_minwidth(frp, NULL);
		if (frp->fr_width + extra_cols < w)
		{
		    extra_cols += frp->fr_width - w;
		    frame_new_width(frp, w, leftfirst, wfw);
		}
		else
		{
		    frame_new_width(frp, frp->fr_width + extra_cols,
							      leftfirst, wfw);
		    break;
		}
		if (leftfirst)
		{
		    do
			frp = frp->fr_next;
		    while (wfw && frp != NULL && frame_fixed_width(frp));
		}
		else
		{
		    do
			frp = frp->fr_prev;
		    while (wfw && frp != NULL && frame_fixed_width(frp));
		}
		// Increase "width" if we could not reduce enough frames.
		if (frp == NULL)
		    width -= extra_cols;
	    }
	}
	else if (extra_cols > 0)
	{
	    // increase width of rightmost frame
	    frame_new_width(frp, frp->fr_width + extra_cols, leftfirst, wfw);
	}
    }
    topfrp->fr_width = width;
}

/*
 * Add the vertical separator to windows at the right side of "frp".
 * Note: Does not check if there is room!
 */
    static void
frame_add_vsep(frame_T *frp)
{
    win_T	*wp;

    if (frp->fr_layout == FR_LEAF)
    {
	wp = frp->fr_win;
	if (wp->w_vsep_width == 0)
	{
	    if (wp->w_width > 0)	// don't make it negative
		--wp->w_width;
	    wp->w_vsep_width = 1;
	}
    }
    else if (frp->fr_layout == FR_COL)
    {
	// Handle all the frames in the column.
	FOR_ALL_FRAMES(frp, frp->fr_child)
	    frame_add_vsep(frp);
    }
    else // frp->fr_layout == FR_ROW
    {
	// Only need to handle the last frame in the row.
	frp = frp->fr_child;
	while (frp->fr_next != NULL)
	    frp = frp->fr_next;
	frame_add_vsep(frp);
    }
}

/*
 * Set frame width from the window it contains.
 */
    static void
frame_fix_width(win_T *wp)
{
    wp->w_frame->fr_width = wp->w_width + wp->w_vsep_width;
}

/*
 * Set frame height from the window it contains.
 */
    static void
frame_fix_height(win_T *wp)
{
    wp->w_frame->fr_height = VISIBLE_HEIGHT(wp) + wp->w_status_height;
}

/*
 * Compute the minimal height for frame "topfrp".
 * Uses the 'winminheight' option.
 * When "next_curwin" isn't NULL, use p_wh for this window.
 * When "next_curwin" is NOWIN, don't use at least one line for the current
 * window.
 */
    static int
frame_minheight(frame_T *topfrp, win_T *next_curwin)
{
    frame_T	*frp;
    int		m;
    int		n;

    if (topfrp->fr_win != NULL)
    {
	if (topfrp->fr_win == next_curwin)
	    m = p_wh + topfrp->fr_win->w_status_height;
	else
	{
	    // window: minimal height of the window plus status line
	    m = p_wmh + topfrp->fr_win->w_status_height;
	    if (topfrp->fr_win == curwin && next_curwin == NULL)
	    {
		// Current window is minimal one line high and WinBar is
		// visible.
		if (p_wmh == 0)
		    ++m;
		m += WINBAR_HEIGHT(curwin);
	    }
	}
    }
    else if (topfrp->fr_layout == FR_ROW)
    {
	// get the minimal height from each frame in this row
	m = 0;
	FOR_ALL_FRAMES(frp, topfrp->fr_child)
	{
	    n = frame_minheight(frp, next_curwin);
	    if (n > m)
		m = n;
	}
    }
    else
    {
	// Add up the minimal heights for all frames in this column.
	m = 0;
	FOR_ALL_FRAMES(frp, topfrp->fr_child)
	    m += frame_minheight(frp, next_curwin);
    }

    return m;
}

/*
 * Compute the minimal width for frame "topfrp".
 * When "next_curwin" isn't NULL, use p_wiw for this window.
 * When "next_curwin" is NOWIN, don't use at least one column for the current
 * window.
 */
    static int
frame_minwidth(
    frame_T	*topfrp,
    win_T	*next_curwin)	// use p_wh and p_wiw for next_curwin
{
    frame_T	*frp;
    int		m, n;

    if (topfrp->fr_win != NULL)
    {
	if (topfrp->fr_win == next_curwin)
	    m = p_wiw + topfrp->fr_win->w_vsep_width;
	else
	{
	    // window: minimal width of the window plus separator column
	    m = p_wmw + topfrp->fr_win->w_vsep_width;
	    // Current window is minimal one column wide
	    if (p_wmw == 0 && topfrp->fr_win == curwin && next_curwin == NULL)
		++m;
	}
    }
    else if (topfrp->fr_layout == FR_COL)
    {
	// get the minimal width from each frame in this column
	m = 0;
	FOR_ALL_FRAMES(frp, topfrp->fr_child)
	{
	    n = frame_minwidth(frp, next_curwin);
	    if (n > m)
		m = n;
	}
    }
    else
    {
	// Add up the minimal widths for all frames in this row.
	m = 0;
	FOR_ALL_FRAMES(frp, topfrp->fr_child)
	    m += frame_minwidth(frp, next_curwin);
    }

    return m;
}


/*
 * Try to close all windows except current one.
 * Buffers in the other windows become hidden if 'hidden' is set, or '!' is
 * used and the buffer was modified.
 *
 * Used by ":bdel" and ":only".
 */
    void
close_others(
    int		message,
    int		forceit)	    // always hide all other windows
{
    win_T	*wp;
    win_T	*nextwp;
    int		r;

    if (one_window())
    {
	if (message && !autocmd_busy)
	    msg(_(m_onlyone));
	return;
    }

    // Be very careful here: autocommands may change the window layout.
    for (wp = firstwin; win_valid(wp); wp = nextwp)
    {
	nextwp = wp->w_next;
	if (wp == curwin)		// don't close current window
	    continue;

	// autoccommands messed this one up
	if (!buf_valid(wp->w_buffer) && win_valid(wp))
	{
	    wp->w_buffer = NULL;
	    win_close(wp, 0);
	    continue;
	}
	// Check if it's allowed to abandon this window
	r = can_abandon(wp->w_buffer, forceit);
	if (!win_valid(wp))		// autocommands messed wp up
	{
	    nextwp = firstwin;
	    continue;
	}
	if (!r)
	{
#if defined(FEAT_GUI_DIALOG) || defined(FEAT_CON_DIALOG)
	    if (message && (p_confirm
			 || (cmdmod.cmod_flags & CMOD_CONFIRM)) && p_write)
	    {
		dialog_changed(wp->w_buffer, FALSE);
		if (!win_valid(wp))		// autocommands messed wp up
		{
		    nextwp = firstwin;
		    continue;
		}
	    }
	    if (bufIsChanged(wp->w_buffer))
#endif
		continue;
	}
	win_close(wp, !buf_hide(wp->w_buffer) && !bufIsChanged(wp->w_buffer));
    }

    if (message && !ONE_WINDOW)
	emsg(_(e_other_window_contains_changes));
}

/*
 * Store the relevant window pointers for tab page "tp".  To be used before
 * use_tabpage().
 */
    void
unuse_tabpage(tabpage_T *tp)
{
    tp->tp_topframe = topframe;
    tp->tp_firstwin = firstwin;
    tp->tp_lastwin = lastwin;
    tp->tp_curwin = curwin;
}

/*
 * Set the relevant pointers to use tab page "tp".  May want to call
 * unuse_tabpage() first.
 */
    void
use_tabpage(tabpage_T *tp)
{
    curtab = tp;
    topframe = curtab->tp_topframe;
    firstwin = curtab->tp_firstwin;
    lastwin = curtab->tp_lastwin;
    curwin = curtab->tp_curwin;
}

/*
 * Allocate the first window and put an empty buffer in it.
 * Called from main().
 * Return FAIL when something goes wrong (out of memory).
 */
    int
win_alloc_first(void)
{
    if (win_alloc_firstwin(NULL) == FAIL)
	return FAIL;

    first_tabpage = alloc_tabpage();
    if (first_tabpage == NULL)
	return FAIL;
    curtab = first_tabpage;
    unuse_tabpage(first_tabpage);

    return OK;
}

/*
 * Allocate and init a window that is not a regular window.
 * This can only be done after the first window is fully initialized, thus it
 * can't be in win_alloc_first().
 */
    win_T *
win_alloc_popup_win(void)
{
    win_T *wp;

    wp = win_alloc(NULL, TRUE);
    if (wp == NULL)
	return NULL;
    // We need to initialize options with something, using the current
    // window makes most sense.
    win_init_some(wp, curwin);

    RESET_BINDING(wp);
    new_frame(wp);
    return wp;
}

/*
 * Initialize window "wp" to display buffer "buf".
 */
    void
win_init_popup_win(win_T *wp, buf_T *buf)
{
    wp->w_buffer = buf;
    ++buf->b_nwindows;
    win_init_empty(wp); // set cursor and topline to safe values

    // Make sure w_localdir and globaldir are NULL to avoid a chdir() in
    // win_enter_ext().
    VIM_CLEAR(wp->w_localdir);
}

/*
 * Allocate the first window or the first window in a new tab page.
 * When "oldwin" is NULL create an empty buffer for it.
 * When "oldwin" is not NULL copy info from it to the new window.
 * Return FAIL when something goes wrong (out of memory).
 */
    static int
win_alloc_firstwin(win_T *oldwin)
{
    curwin = win_alloc(NULL, FALSE);
    if (curwin == NULL)
	return FAIL;
    if (oldwin == NULL)
    {
	// Very first window, need to create an empty buffer for it and
	// initialize from scratch.
	curbuf = buflist_new(NULL, NULL, 1L, BLN_LISTED);
	if (curwin == NULL || curbuf == NULL)
	    return FAIL;
	curwin->w_buffer = curbuf;
#ifdef FEAT_SYN_HL
	curwin->w_s = &(curbuf->b_s);
#endif
	curbuf->b_nwindows = 1;	// there is one window
	curwin->w_alist = &global_alist;
	curwin_init();		// init current window
    }
    else
    {
	// First window in new tab page, initialize it from "oldwin".
	win_init(curwin, oldwin, 0);

	// We don't want cursor- and scroll-binding in the first window.
	RESET_BINDING(curwin);
    }

    new_frame(curwin);
    if (curwin->w_frame == NULL)
	return FAIL;
    topframe = curwin->w_frame;
    topframe->fr_width = Columns;
    topframe->fr_height = Rows - p_ch;

    return OK;
}

/*
 * Create a frame for window "wp".
 */
    static void
new_frame(win_T *wp)
{
    frame_T *frp = ALLOC_CLEAR_ONE(frame_T);

    wp->w_frame = frp;
    if (frp == NULL)
	return;
    frp->fr_layout = FR_LEAF;
    frp->fr_win = wp;
}

/*
 * Initialize the window and frame size to the maximum.
 */
    void
win_init_size(void)
{
    firstwin->w_height = ROWS_AVAIL;
    firstwin->w_prev_height = ROWS_AVAIL;
    topframe->fr_height = ROWS_AVAIL;
    firstwin->w_width = Columns;
    topframe->fr_width = Columns;
}

/*
 * Allocate a new tabpage_T and init the values.
 * Returns NULL when out of memory.
 */
    static tabpage_T *
alloc_tabpage(void)
{
    tabpage_T	*tp;
# ifdef FEAT_GUI
    int		i;
# endif


    tp = ALLOC_CLEAR_ONE(tabpage_T);
    if (tp == NULL)
	return NULL;

# ifdef FEAT_EVAL
    // init t: variables
    tp->tp_vars = dict_alloc_id(aid_newtabpage_tvars);
    if (tp->tp_vars == NULL)
    {
	vim_free(tp);
	return NULL;
    }
    init_var_dict(tp->tp_vars, &tp->tp_winvar, VAR_SCOPE);
# endif

# ifdef FEAT_GUI
    for (i = 0; i < 3; i++)
	tp->tp_prev_which_scrollbars[i] = -1;
# endif
# ifdef FEAT_DIFF
    tp->tp_diff_invalid = TRUE;
# endif
    tp->tp_ch_used = p_ch;

    return tp;
}

    void
free_tabpage(tabpage_T *tp)
{
    int idx;

# ifdef FEAT_DIFF
    diff_clear(tp);
# endif
# ifdef FEAT_PROP_POPUP
    while (tp->tp_first_popupwin != NULL)
	popup_close_tabpage(tp, tp->tp_first_popupwin->w_id, TRUE);
#endif
    for (idx = 0; idx < SNAP_COUNT; ++idx)
	clear_snapshot(tp, idx);
#ifdef FEAT_EVAL
    vars_clear(&tp->tp_vars->dv_hashtab);	// free all t: variables
    hash_init(&tp->tp_vars->dv_hashtab);
    unref_var_dict(tp->tp_vars);
#endif

    if (tp == lastused_tabpage)
	lastused_tabpage = NULL;

    vim_free(tp->tp_localdir);
    vim_free(tp->tp_prevdir);

#ifdef FEAT_PYTHON
    python_tabpage_free(tp);
#endif

#ifdef FEAT_PYTHON3
    python3_tabpage_free(tp);
#endif

    vim_free(tp);
}

/*
 * Create a new Tab page with one window.
 * It will edit the current buffer, like after ":split".
 * When "after" is 0 put it just after the current Tab page.
 * Otherwise put it just before tab page "after".
 * Return FAIL or OK.
 */
    int
win_new_tabpage(int after)
{
    tabpage_T	*tp = curtab;
    tabpage_T	*prev_tp = curtab;
    tabpage_T	*newtp;
    int		n;

    if (cmdwin_type != 0)
    {
	emsg(_(e_invalid_in_cmdline_window));
	return FAIL;
    }
    if (window_layout_locked(CMD_tabnew))
	return FAIL;

    newtp = alloc_tabpage();
    if (newtp == NULL)
	return FAIL;

    // Remember the current windows in this Tab page.
    if (leave_tabpage(curbuf, TRUE) == FAIL)
    {
	vim_free(newtp);
	return FAIL;
    }
    curtab = newtp;

    newtp->tp_localdir = (tp->tp_localdir == NULL)
				    ? NULL : vim_strsave(tp->tp_localdir);
    // Create a new empty window.
    if (win_alloc_firstwin(tp->tp_curwin) == OK)
    {
	// Make the new Tab page the new topframe.
	if (after == 1)
	{
	    // New tab page becomes the first one.
	    newtp->tp_next = first_tabpage;
	    first_tabpage = newtp;
	}
	else
	{
	    if (after > 0)
	    {
		// Put new tab page before tab page "after".
		n = 2;
		for (tp = first_tabpage; tp->tp_next != NULL
					       && n < after; tp = tp->tp_next)
		    ++n;
	    }
	    newtp->tp_next = tp->tp_next;
	    tp->tp_next = newtp;
	}
	newtp->tp_firstwin = newtp->tp_lastwin = newtp->tp_curwin = curwin;

	win_init_size();
	firstwin->w_winrow = tabline_height();
	firstwin->w_prev_winrow = firstwin->w_winrow;
	win_comp_scroll(curwin);

	newtp->tp_topframe = topframe;
	last_status(FALSE);

	lastused_tabpage = prev_tp;

#if defined(FEAT_GUI)
	// When 'guioptions' includes 'L' or 'R' may have to remove or add
	// scrollbars.  Have to update them anyway.
	gui_may_update_scrollbars();
#endif
#ifdef FEAT_JOB_CHANNEL
	entering_window(curwin);
#endif

	redraw_all_later(UPD_NOT_VALID);
	apply_autocmds(EVENT_WINNEW, NULL, NULL, FALSE, curbuf);
	apply_autocmds(EVENT_WINENTER, NULL, NULL, FALSE, curbuf);
	apply_autocmds(EVENT_TABNEW, NULL, NULL, FALSE, curbuf);
	apply_autocmds(EVENT_TABENTER, NULL, NULL, FALSE, curbuf);
	return OK;
    }

    // Failed, get back the previous Tab page
    enter_tabpage(curtab, curbuf, TRUE, TRUE);
    return FAIL;
}

/*
 * Open a new tab page if ":tab cmd" was used.  It will edit the same buffer,
 * like with ":split".
 * Returns OK if a new tab page was created, FAIL otherwise.
 */
    static int
may_open_tabpage(void)
{
    int		n = (cmdmod.cmod_tab == 0)
				       ? postponed_split_tab : cmdmod.cmod_tab;

    if (n == 0)
	return FAIL;

    cmdmod.cmod_tab = 0;	    // reset it to avoid doing it twice
    postponed_split_tab = 0;
    return win_new_tabpage(n);
}

/*
 * Create up to "maxcount" tabpages with empty windows.
 * Returns the number of resulting tab pages.
 */
    int
make_tabpages(int maxcount)
{
    int		count = maxcount;
    int		todo;

    // Limit to 'tabpagemax' tabs.
    if (count > p_tpm)
	count = p_tpm;

    /*
     * Don't execute autocommands while creating the tab pages.  Must do that
     * when putting the buffers in the windows.
     */
    block_autocmds();

    for (todo = count - 1; todo > 0; --todo)
	if (win_new_tabpage(0) == FAIL)
	    break;

    unblock_autocmds();

    // return actual number of tab pages
    return (count - todo);
}

/*
 * Return TRUE when "tpc" points to a valid tab page.
 */
    int
valid_tabpage(tabpage_T *tpc)
{
    tabpage_T	*tp;

    FOR_ALL_TABPAGES(tp)
	if (tp == tpc)
	    return TRUE;
    return FALSE;
}

/*
 * Return TRUE when "tpc" points to a valid tab page and at least one window is
 * valid.
 */
    int
valid_tabpage_win(tabpage_T *tpc)
{
    tabpage_T	*tp;
    win_T	*wp;

    FOR_ALL_TABPAGES(tp)
    {
	if (tp == tpc)
	{
	    FOR_ALL_WINDOWS_IN_TAB(tp, wp)
	    {
		if (win_valid_any_tab(wp))
		    return TRUE;
	    }
	    return FALSE;
	}
    }
    // shouldn't happen
    return FALSE;
}

/*
 * Close tabpage "tab", assuming it has no windows in it.
 * There must be another tabpage or this will crash.
 */
    void
close_tabpage(tabpage_T *tab)
{
    tabpage_T	*ptp;

    if (tab == first_tabpage)
    {
	first_tabpage = tab->tp_next;
	ptp = first_tabpage;
    }
    else
    {
	for (ptp = first_tabpage; ptp != NULL && ptp->tp_next != tab;
							    ptp = ptp->tp_next)
	    ;
	assert(ptp != NULL);
	ptp->tp_next = tab->tp_next;
    }

    goto_tabpage_tp(ptp, FALSE, FALSE);
    free_tabpage(tab);
}

/*
 * Find tab page "n" (first one is 1).  Returns NULL when not found.
 */
    tabpage_T *
find_tabpage(int n)
{
    tabpage_T	*tp;
    int		i = 1;

    if (n == 0)
	return curtab;

    for (tp = first_tabpage; tp != NULL && i != n; tp = tp->tp_next)
	++i;
    return tp;
}

/*
 * Get index of tab page "tp".  First one has index 1.
 * When not found returns number of tab pages plus one.
 */
    int
tabpage_index(tabpage_T *ftp)
{
    int		i = 1;
    tabpage_T	*tp;

    for (tp = first_tabpage; tp != NULL && tp != ftp; tp = tp->tp_next)
	++i;
    return i;
}

/*
 * Prepare for leaving the current tab page.
 * When autocommands change "curtab" we don't leave the tab page and return
 * FAIL.
 * Careful: When OK is returned need to get a new tab page very very soon!
 */
    static int
leave_tabpage(
    buf_T	*new_curbuf UNUSED,    // what is going to be the new curbuf,
				       // NULL if unknown
    int		trigger_leave_autocmds)
{
    tabpage_T	*tp = curtab;

#ifdef FEAT_JOB_CHANNEL
    leaving_window(curwin);
#endif
    reset_VIsual_and_resel();	// stop Visual mode
    if (trigger_leave_autocmds)
    {
	if (new_curbuf != curbuf)
	{
	    apply_autocmds(EVENT_BUFLEAVE, NULL, NULL, FALSE, curbuf);
	    if (curtab != tp)
		return FAIL;
	}
	apply_autocmds(EVENT_WINLEAVE, NULL, NULL, FALSE, curbuf);
	if (curtab != tp)
	    return FAIL;
	apply_autocmds(EVENT_TABLEAVE, NULL, NULL, FALSE, curbuf);
	if (curtab != tp)
	    return FAIL;
    }

    reset_dragwin();
#if defined(FEAT_GUI)
    // Remove the scrollbars.  They may be added back later.
    if (gui.in_use)
	gui_remove_scrollbars();
#endif
    tp->tp_curwin = curwin;
    tp->tp_prevwin = prevwin;
    tp->tp_firstwin = firstwin;
    tp->tp_lastwin = lastwin;
    tp->tp_old_Rows = Rows;
    if (tp->tp_old_Columns != -1)
	tp->tp_old_Columns = Columns;
    firstwin = NULL;
    lastwin = NULL;
    return OK;
}

/*
 * Start using tab page "tp".
 * Only to be used after leave_tabpage() or freeing the current tab page.
 * Only trigger *Enter autocommands when trigger_enter_autocmds is TRUE.
 * Only trigger *Leave autocommands when trigger_leave_autocmds is TRUE.
 */
    static void
enter_tabpage(
    tabpage_T	*tp,
    buf_T	*old_curbuf UNUSED,
    int		trigger_enter_autocmds,
    int		trigger_leave_autocmds)
{
    int		row;
    int		old_off = tp->tp_firstwin->w_winrow;
    win_T	*next_prevwin = tp->tp_prevwin;
    tabpage_T	*last_tab = curtab;

    use_tabpage(tp);

    // We would like doing the TabEnter event first, but we don't have a
    // valid current window yet, which may break some commands.
    // This triggers autocommands, thus may make "tp" invalid.
    (void)win_enter_ext(tp->tp_curwin, WEE_CURWIN_INVALID
		  | (trigger_enter_autocmds ? WEE_TRIGGER_ENTER_AUTOCMDS : 0)
		  | (trigger_leave_autocmds ? WEE_TRIGGER_LEAVE_AUTOCMDS : 0));
    prevwin = next_prevwin;

    last_status(FALSE);		// status line may appear or disappear
    row = win_comp_pos();	// recompute w_winrow for all windows
#ifdef FEAT_DIFF
    diff_need_scrollbind = TRUE;
#endif

    // Use the stored value of p_ch, so that it can be different for each tab
    // page.
    if (p_ch != curtab->tp_ch_used)
	clear_cmdline = TRUE;
    p_ch = curtab->tp_ch_used;

    // When cmdheight is changed in a tab page with '<C-w>-', cmdline_row is
    // changed but p_ch and tp_ch_used are not changed. Thus we also need to
    // check cmdline_row.
    if (row < cmdline_row && cmdline_row <= Rows - p_ch)
	clear_cmdline = TRUE;

    // If there was a click in a window, it won't be usable for a following
    // drag.
    reset_dragwin();

    // The tabpage line may have appeared or disappeared, may need to resize
    // the frames for that.  When the Vim window was resized need to update
    // frame sizes too.
    if (curtab->tp_old_Rows != Rows || (old_off != firstwin->w_winrow
#ifdef FEAT_GUI_TABLINE
			    && !gui_use_tabline()
#endif
		))
	shell_new_rows();
    if (curtab->tp_old_Columns != Columns)
    {
	if (starting == 0)
	{
	    shell_new_columns();	// update window widths
	    curtab->tp_old_Columns = Columns;
	}
	else
	    curtab->tp_old_Columns = -1;  // update window widths later
    }

    lastused_tabpage = last_tab;

#if defined(FEAT_GUI)
    // When 'guioptions' includes 'L' or 'R' may have to remove or add
    // scrollbars.  Have to update them anyway.
    gui_may_update_scrollbars();
#endif

    // Apply autocommands after updating the display, when 'rows' and
    // 'columns' have been set correctly.
    if (trigger_enter_autocmds)
    {
	apply_autocmds(EVENT_TABENTER, NULL, NULL, FALSE, curbuf);
	if (old_curbuf != curbuf)
	    apply_autocmds(EVENT_BUFENTER, NULL, NULL, FALSE, curbuf);
    }

    redraw_all_later(UPD_NOT_VALID);
}

/*
 * Go to tab page "n".  For ":tab N" and "Ngt".
 * When "n" is 9999 go to the last tab page.
 */
    void
goto_tabpage(int n)
{
    tabpage_T	*tp = NULL;  // shut up compiler
    tabpage_T	*ttp;
    int		i;

    if (text_locked())
    {
	// Not allowed when editing the command line.
	text_locked_msg();
	return;
    }

    // If there is only one it can't work.
    if (first_tabpage->tp_next == NULL)
    {
	if (n > 1)
	    beep_flush();
	return;
    }

    if (n == 0)
    {
	// No count, go to next tab page, wrap around end.
	if (curtab->tp_next == NULL)
	    tp = first_tabpage;
	else
	    tp = curtab->tp_next;
    }
    else if (n < 0)
    {
	// "gT": go to previous tab page, wrap around end.  "N gT" repeats
	// this N times.
	ttp = curtab;
	for (i = n; i < 0; ++i)
	{
	    for (tp = first_tabpage; tp->tp_next != ttp && tp->tp_next != NULL;
		    tp = tp->tp_next)
		;
	    ttp = tp;
	}
    }
    else if (n == 9999)
    {
	// Go to last tab page.
	for (tp = first_tabpage; tp->tp_next != NULL; tp = tp->tp_next)
	    ;
    }
    else
    {
	// Go to tab page "n".
	tp = find_tabpage(n);
	if (tp == NULL)
	{
	    beep_flush();
	    return;
	}
    }

    goto_tabpage_tp(tp, TRUE, TRUE);

#ifdef FEAT_GUI_TABLINE
    if (gui_use_tabline())
	gui_mch_set_curtab(tabpage_index(curtab));
#endif
}

/*
 * Go to tabpage "tp".
 * Only trigger *Enter autocommands when trigger_enter_autocmds is TRUE.
 * Only trigger *Leave autocommands when trigger_leave_autocmds is TRUE.
 * Note: doesn't update the GUI tab.
 */
    void
goto_tabpage_tp(
    tabpage_T	*tp,
    int		trigger_enter_autocmds,
    int		trigger_leave_autocmds)
{
    if (trigger_enter_autocmds || trigger_leave_autocmds)
	CHECK_CMDWIN;

    // Don't repeat a message in another tab page.
    set_keep_msg(NULL, 0);

    skip_win_fix_scroll = TRUE;
    if (tp != curtab && leave_tabpage(tp->tp_curwin->w_buffer,
					trigger_leave_autocmds) == OK)
    {
	if (valid_tabpage(tp))
	    enter_tabpage(tp, curbuf, trigger_enter_autocmds,
		    trigger_leave_autocmds);
	else
	    enter_tabpage(curtab, curbuf, trigger_enter_autocmds,
		    trigger_leave_autocmds);
    }
    skip_win_fix_scroll = FALSE;
}

/*
 * Go to the last accessed tab page, if there is one.
 * Return OK or FAIL
 */
    int
goto_tabpage_lastused(void)
{
    if (!valid_tabpage(lastused_tabpage))
	return FAIL;

    goto_tabpage_tp(lastused_tabpage, TRUE, TRUE);
    return OK;
}

/*
 * Enter window "wp" in tab page "tp".
 * Also updates the GUI tab.
 */
    void
goto_tabpage_win(tabpage_T *tp, win_T *wp)
{
    goto_tabpage_tp(tp, TRUE, TRUE);
    if (curtab == tp && win_valid(wp))
    {
	win_enter(wp, TRUE);
# ifdef FEAT_GUI_TABLINE
	if (gui_use_tabline())
	    gui_mch_set_curtab(tabpage_index(curtab));
# endif
    }
}

/*
 * Move the current tab page to after tab page "nr".
 */
    void
tabpage_move(int nr)
{
    int		n = 1;
    tabpage_T	*tp, *tp_dst;

    if (first_tabpage->tp_next == NULL)
	return;

    for (tp = first_tabpage; tp->tp_next != NULL && n < nr; tp = tp->tp_next)
	++n;

    if (tp == curtab || (nr > 0 && tp->tp_next != NULL
						    && tp->tp_next == curtab))
	return;

    tp_dst = tp;

    // Remove the current tab page from the list of tab pages.
    if (curtab == first_tabpage)
	first_tabpage = curtab->tp_next;
    else
    {
	FOR_ALL_TABPAGES(tp)
	    if (tp->tp_next == curtab)
		break;
	if (tp == NULL)	// "cannot happen"
	    return;
	tp->tp_next = curtab->tp_next;
    }

    // Re-insert it at the specified position.
    if (nr <= 0)
    {
	curtab->tp_next = first_tabpage;
	first_tabpage = curtab;
    }
    else
    {
	curtab->tp_next = tp_dst->tp_next;
	tp_dst->tp_next = curtab;
    }

    // Need to redraw the tabline.  Tab page contents doesn't change.
    redraw_tabline = TRUE;
}


/*
 * Go to another window.
 * When jumping to another buffer, stop Visual mode.  Do this before
 * changing windows so we can yank the selection into the '*' register.
 * When jumping to another window on the same buffer, adjust its cursor
 * position to keep the same Visual area.
 */
    void
win_goto(win_T *wp)
{
#ifdef FEAT_CONCEAL
    win_T	*owp = curwin;
#endif

#ifdef FEAT_PROP_POPUP
    if (ERROR_IF_ANY_POPUP_WINDOW)
	return;
    if (popup_is_popup(wp))
    {
	emsg(_(e_not_allowed_to_enter_popup_window));
	return;
    }
#endif
    if (text_or_buf_locked())
    {
	beep_flush();
	return;
    }

    if (wp->w_buffer != curbuf)
	reset_VIsual_and_resel();
    else if (VIsual_active)
	wp->w_cursor = curwin->w_cursor;

#ifdef FEAT_GUI
    need_mouse_correct = TRUE;
#endif
    win_enter(wp, TRUE);

#ifdef FEAT_CONCEAL
    // Conceal cursor line in previous window, unconceal in current window.
    if (win_valid(owp) && owp->w_p_cole > 0 && !msg_scrolled)
	redrawWinline(owp, owp->w_cursor.lnum);
    if (curwin->w_p_cole > 0 && !msg_scrolled)
	need_cursor_line_redraw = TRUE;
#endif
}

#if defined(FEAT_PERL) || defined(PROTO)
/*
 * Find window number "winnr" (counting top to bottom).
 */
    win_T *
win_find_nr(int winnr)
{
    win_T	*wp;

    FOR_ALL_WINDOWS(wp)
	if (--winnr == 0)
	    break;
    return wp;
}
#endif

#if ((defined(FEAT_PYTHON) || defined(FEAT_PYTHON3))) || defined(PROTO)
/*
 * Find the tabpage for window "win".
 */
    tabpage_T *
win_find_tabpage(win_T *win)
{
    win_T	*wp;
    tabpage_T	*tp;

    FOR_ALL_TAB_WINDOWS(tp, wp)
	    if (wp == win)
		return tp;
    return NULL;
}
#endif

/*
 * Get the above or below neighbor window of the specified window.
 *   up - TRUE for the above neighbor
 *   count - nth neighbor window
 * Returns the specified window if the neighbor is not found.
 */
    win_T *
win_vert_neighbor(tabpage_T *tp, win_T *wp, int up, long count)
{
    frame_T	*fr;
    frame_T	*nfr;
    frame_T	*foundfr;

#ifdef FEAT_PROP_POPUP
    if (popup_is_popup(wp))
	// popups don't have neighbors.
	return NULL;
#endif
    foundfr = wp->w_frame;
    while (count--)
    {
	/*
	 * First go upwards in the tree of frames until we find a upwards or
	 * downwards neighbor.
	 */
	fr = foundfr;
	for (;;)
	{
	    if (fr == tp->tp_topframe)
		goto end;
	    if (up)
		nfr = fr->fr_prev;
	    else
		nfr = fr->fr_next;
	    if (fr->fr_parent->fr_layout == FR_COL && nfr != NULL)
		break;
	    fr = fr->fr_parent;
	}

	/*
	 * Now go downwards to find the bottom or top frame in it.
	 */
	for (;;)
	{
	    if (nfr->fr_layout == FR_LEAF)
	    {
		foundfr = nfr;
		break;
	    }
	    fr = nfr->fr_child;
	    if (nfr->fr_layout == FR_ROW)
	    {
		// Find the frame at the cursor row.
		while (fr->fr_next != NULL
			&& frame2win(fr)->w_wincol + fr->fr_width
					 <= wp->w_wincol + wp->w_wcol)
		    fr = fr->fr_next;
	    }
	    if (nfr->fr_layout == FR_COL && up)
		while (fr->fr_next != NULL)
		    fr = fr->fr_next;
	    nfr = fr;
	}
    }
end:
    return foundfr != NULL ? foundfr->fr_win : NULL;
}

/*
 * Move to window above or below "count" times.
 */
    static void
win_goto_ver(
    int		up,		// TRUE to go to win above
    long	count)
{
    win_T	*win;

#ifdef FEAT_PROP_POPUP
    if (ERROR_IF_TERM_POPUP_WINDOW)
	return;
#endif
    win = win_vert_neighbor(curtab, curwin, up, count);
    if (win != NULL)
	win_goto(win);
}

/*
 * Get the left or right neighbor window of the specified window.
 *   left - TRUE for the left neighbor
 *   count - nth neighbor window
 * Returns the specified window if the neighbor is not found.
 */
    win_T *
win_horz_neighbor(tabpage_T *tp, win_T *wp, int left, long count)
{
    frame_T	*fr;
    frame_T	*nfr;
    frame_T	*foundfr;

#ifdef FEAT_PROP_POPUP
    if (popup_is_popup(wp))
	// popups don't have neighbors.
	return NULL;
#endif
    foundfr = wp->w_frame;
    while (count--)
    {
	/*
	 * First go upwards in the tree of frames until we find a left or
	 * right neighbor.
	 */
	fr = foundfr;
	for (;;)
	{
	    if (fr == tp->tp_topframe)
		goto end;
	    if (left)
		nfr = fr->fr_prev;
	    else
		nfr = fr->fr_next;
	    if (fr->fr_parent->fr_layout == FR_ROW && nfr != NULL)
		break;
	    fr = fr->fr_parent;
	}

	/*
	 * Now go downwards to find the leftmost or rightmost frame in it.
	 */
	for (;;)
	{
	    if (nfr->fr_layout == FR_LEAF)
	    {
		foundfr = nfr;
		break;
	    }
	    fr = nfr->fr_child;
	    if (nfr->fr_layout == FR_COL)
	    {
		// Find the frame at the cursor row.
		while (fr->fr_next != NULL
			&& frame2win(fr)->w_winrow + fr->fr_height
					 <= wp->w_winrow + wp->w_wrow)
		    fr = fr->fr_next;
	    }
	    if (nfr->fr_layout == FR_ROW && left)
		while (fr->fr_next != NULL)
		    fr = fr->fr_next;
	    nfr = fr;
	}
    }
end:
    return foundfr != NULL ? foundfr->fr_win : NULL;
}

/*
 * Move to left or right window.
 */
    static void
win_goto_hor(
    int		left,		// TRUE to go to left win
    long	count)
{
    win_T	*win;

#ifdef FEAT_PROP_POPUP
    if (ERROR_IF_TERM_POPUP_WINDOW)
	return;
#endif
    win = win_horz_neighbor(curtab, curwin, left, count);
    if (win != NULL)
	win_goto(win);
}

/*
 * Make window "wp" the current window.
 */
    void
win_enter(win_T *wp, int undo_sync)
{
    (void)win_enter_ext(wp, (undo_sync ? WEE_UNDO_SYNC : 0)
		    | WEE_TRIGGER_ENTER_AUTOCMDS | WEE_TRIGGER_LEAVE_AUTOCMDS);
}

/*
 * Used after making another window the current one: change directory if
 * needed.
 */
    static void
fix_current_dir(void)
{
    if (curwin->w_localdir != NULL || curtab->tp_localdir != NULL)
    {
	char_u	*dirname;

	// Window or tab has a local directory: Save current directory as
	// global directory (unless that was done already) and change to the
	// local directory.
	if (globaldir == NULL)
	{
	    char_u	cwd[MAXPATHL];

	    if (mch_dirname(cwd, MAXPATHL) == OK)
		globaldir = vim_strsave(cwd);
	}
	if (curwin->w_localdir != NULL)
	    dirname = curwin->w_localdir;
	else
	    dirname = curtab->tp_localdir;

	if (mch_chdir((char *)dirname) == 0)
	{
	    last_chdir_reason = NULL;
	    shorten_fnames(TRUE);
	}
    }
    else if (globaldir != NULL)
    {
	// Window doesn't have a local directory and we are not in the global
	// directory: Change to the global directory.
	vim_ignored = mch_chdir((char *)globaldir);
	VIM_CLEAR(globaldir);
	last_chdir_reason = NULL;
	shorten_fnames(TRUE);
    }
}

/*
 * Make window "wp" the current window.
 * Can be called with "flags" containing WEE_CURWIN_INVALID, which means that
 * curwin has just been closed and isn't valid.
 * Returns TRUE when dont_parse_messages was decremented.
 */
    static int
win_enter_ext(win_T *wp, int flags)
{
    int		other_buffer = FALSE;
    int		curwin_invalid = (flags & WEE_CURWIN_INVALID);
    int		did_decrement = FALSE;

    if (wp == curwin && curwin_invalid == 0)	// nothing to do
	return FALSE;

#ifdef FEAT_JOB_CHANNEL
    if (curwin_invalid == 0)
	leaving_window(curwin);
#endif

    if (curwin_invalid == 0 && (flags & WEE_TRIGGER_LEAVE_AUTOCMDS))
    {
	/*
	 * Be careful: If autocommands delete the window, return now.
	 */
	if (wp->w_buffer != curbuf)
	{
	    apply_autocmds(EVENT_BUFLEAVE, NULL, NULL, FALSE, curbuf);
	    other_buffer = TRUE;
	    if (!win_valid(wp))
		return FALSE;
	}
	apply_autocmds(EVENT_WINLEAVE, NULL, NULL, FALSE, curbuf);
	if (!win_valid(wp))
	    return FALSE;
#ifdef FEAT_EVAL
	// autocmds may abort script processing
	if (aborting())
	    return FALSE;
#endif
    }

    // sync undo before leaving the current buffer
    if ((flags & WEE_UNDO_SYNC) && curbuf != wp->w_buffer)
	u_sync(FALSE);

    // Might need to scroll the old window before switching, e.g., when the
    // cursor was moved.
    if (*p_spk == 'c' && curwin_invalid == 0)
	update_topline();

    // may have to copy the buffer options when 'cpo' contains 'S'
    if (wp->w_buffer != curbuf)
	buf_copy_options(wp->w_buffer, BCO_ENTER | BCO_NOHELP);
    if (curwin_invalid == 0)
    {
	prevwin = curwin;	// remember for CTRL-W p
	curwin->w_redr_status = TRUE;
    }
    curwin = wp;
    curbuf = wp->w_buffer;
    check_cursor();
    if (!virtual_active())
	curwin->w_cursor.coladd = 0;
    if (*p_spk == 'c')		// assume cursor position needs updating
	changed_line_abv_curs();
    else
	// Make sure the cursor position is valid, either by moving the cursor
	// or by scrolling the text.
	win_fix_cursor(
		get_real_state() & (MODE_NORMAL|MODE_CMDLINE|MODE_TERMINAL));

    // Now it is OK to parse messages again, which may be needed in
    // autocommands.
#ifdef MESSAGE_QUEUE
    if (flags & WEE_ALLOW_PARSE_MESSAGES)
    {
	--dont_parse_messages;
	did_decrement = TRUE;
    }
#endif

    fix_current_dir();

#ifdef FEAT_JOB_CHANNEL
    entering_window(curwin);
#endif
    // Careful: autocommands may close the window and make "wp" invalid
    if (flags & WEE_TRIGGER_NEW_AUTOCMDS)
	apply_autocmds(EVENT_WINNEW, NULL, NULL, FALSE, curbuf);
    if (flags & WEE_TRIGGER_ENTER_AUTOCMDS)
    {
	apply_autocmds(EVENT_WINENTER, NULL, NULL, FALSE, curbuf);
	if (other_buffer)
	    apply_autocmds(EVENT_BUFENTER, NULL, NULL, FALSE, curbuf);
    }

    maketitle();
    curwin->w_redr_status = TRUE;
#ifdef FEAT_TERMINAL
    if (bt_terminal(curwin->w_buffer))
	// terminal is likely in another mode
	redraw_mode = TRUE;
#endif
    redraw_tabline = TRUE;
    if (restart_edit)
	redraw_later(UPD_VALID);	// causes status line redraw

    // set window height to desired minimal value
    if (curwin->w_height < p_wh && !curwin->w_p_wfh
#ifdef FEAT_PROP_POPUP
	    && !popup_is_popup(curwin)
#endif
	    )
	win_setheight((int)p_wh);
    else if (curwin->w_height == 0)
	win_setheight(1);

    // set window width to desired minimal value
    if (curwin->w_width < p_wiw && !curwin->w_p_wfw)
	win_setwidth((int)p_wiw);

    setmouse();			// in case jumped to/from help buffer

    // Change directories when the 'acd' option is set.
    DO_AUTOCHDIR;

    return did_decrement;
}

/*
 * Jump to the first open window that contains buffer "buf", if one exists.
 * Returns a pointer to the window found, otherwise NULL.
 */
    win_T *
buf_jump_open_win(buf_T *buf)
{
    win_T	*wp = NULL;

    if (curwin->w_buffer == buf)
	wp = curwin;
    else
	FOR_ALL_WINDOWS(wp)
	    if (wp->w_buffer == buf)
		break;
    if (wp != NULL)
	win_enter(wp, FALSE);
    return wp;
}

/*
 * Jump to the first open window in any tab page that contains buffer "buf",
 * if one exists. First search in the windows present in the current tab page.
 * Returns a pointer to the window found, otherwise NULL.
 */
    win_T *
buf_jump_open_tab(buf_T *buf)
{
    win_T	*wp = buf_jump_open_win(buf);
    tabpage_T	*tp;

    if (wp != NULL)
	return wp;

    FOR_ALL_TABPAGES(tp)
	if (tp != curtab)
	{
	    FOR_ALL_WINDOWS_IN_TAB(tp, wp)
		if (wp->w_buffer == buf)
		    break;
	    if (wp != NULL)
	    {
		goto_tabpage_win(tp, wp);
		if (curwin != wp)
		    wp = NULL;	// something went wrong
		break;
	    }
	}
    return wp;
}

static int last_win_id = LOWEST_WIN_ID - 1;

/*
 * Allocate a window structure and link it in the window list when "hidden" is
 * FALSE.
 */
    static win_T *
win_alloc(win_T *after, int hidden)
{
    win_T	*new_wp;

    /*
     * allocate window structure and linesizes arrays
     */
    new_wp = ALLOC_CLEAR_ONE(win_T);
    if (new_wp == NULL)
	return NULL;

    if (win_alloc_lines(new_wp) == FAIL)
    {
	vim_free(new_wp);
	return NULL;
    }

    new_wp->w_id = ++last_win_id;

#ifdef FEAT_EVAL
    // init w: variables
    new_wp->w_vars = dict_alloc_id(aid_newwin_wvars);
    if (new_wp->w_vars == NULL)
    {
	win_free_lsize(new_wp);
	vim_free(new_wp);
	return NULL;
    }
    init_var_dict(new_wp->w_vars, &new_wp->w_winvar, VAR_SCOPE);
#endif

    // Don't execute autocommands while the window is not properly
    // initialized yet.  gui_create_scrollbar() may trigger a FocusGained
    // event.
    block_autocmds();

    /*
     * link the window in the window list
     */
    if (!hidden)
	win_append(after, new_wp);
    new_wp->w_wincol = 0;
    new_wp->w_width = Columns;

    // position the display and the cursor at the top of the file.
    new_wp->w_topline = 1;
#ifdef FEAT_DIFF
    new_wp->w_topfill = 0;
#endif
    new_wp->w_botline = 2;
    new_wp->w_cursor.lnum = 1;
    new_wp->w_scbind_pos = 1;

    // use global option value for global-local options
    new_wp->w_allbuf_opt.wo_so = new_wp->w_p_so = -1;
    new_wp->w_allbuf_opt.wo_siso = new_wp->w_p_siso = -1;

    // We won't calculate w_fraction until resizing the window
    new_wp->w_fraction = 0;
    new_wp->w_prev_fraction_row = -1;

#ifdef FEAT_GUI
    if (gui.in_use)
    {
	gui_create_scrollbar(&new_wp->w_scrollbars[SBAR_LEFT],
		SBAR_LEFT, new_wp);
	gui_create_scrollbar(&new_wp->w_scrollbars[SBAR_RIGHT],
		SBAR_RIGHT, new_wp);
    }
#endif
#ifdef FEAT_FOLDING
    foldInitWin(new_wp);
#endif
    unblock_autocmds();
#ifdef FEAT_SEARCH_EXTRA
    new_wp->w_next_match_id = 1000;  // up to 1000 can be picked by the user
#endif
    return new_wp;
}

/*
 * Remove window 'wp' from the window list and free the structure.
 */
    static void
win_free(
    win_T	*wp,
    tabpage_T	*tp)		// tab page "win" is in, NULL for current
{
    int		i;
    buf_T	*buf;
    wininfo_T	*wip;

#ifdef FEAT_FOLDING
    clearFolding(wp);
#endif

    // reduce the reference count to the argument list.
    alist_unlink(wp->w_alist);

    // Don't execute autocommands while the window is halfway being deleted.
    // gui_mch_destroy_scrollbar() may trigger a FocusGained event.
    block_autocmds();

#ifdef FEAT_LUA
    lua_window_free(wp);
#endif

#ifdef FEAT_MZSCHEME
    mzscheme_window_free(wp);
#endif

#ifdef FEAT_PERL
    perl_win_free(wp);
#endif

#ifdef FEAT_PYTHON
    python_window_free(wp);
#endif

#ifdef FEAT_PYTHON3
    python3_window_free(wp);
#endif

#ifdef FEAT_TCL
    tcl_window_free(wp);
#endif

#ifdef FEAT_RUBY
    ruby_window_free(wp);
#endif

    clear_winopt(&wp->w_onebuf_opt);
    clear_winopt(&wp->w_allbuf_opt);

    vim_free(wp->w_lcs_chars.multispace);
    vim_free(wp->w_lcs_chars.leadmultispace);

#ifdef FEAT_EVAL
    vars_clear(&wp->w_vars->dv_hashtab);	// free all w: variables
    hash_init(&wp->w_vars->dv_hashtab);
    unref_var_dict(wp->w_vars);
#endif

    {
	tabpage_T	*ttp;

	if (prevwin == wp)
	    prevwin = NULL;
	FOR_ALL_TABPAGES(ttp)
	    if (ttp->tp_prevwin == wp)
		ttp->tp_prevwin = NULL;
    }
    win_free_lsize(wp);

    for (i = 0; i < wp->w_tagstacklen; ++i)
    {
	vim_free(wp->w_tagstack[i].tagname);
	vim_free(wp->w_tagstack[i].user_data);
    }
    vim_free(wp->w_localdir);
    vim_free(wp->w_prevdir);

    // Remove the window from the b_wininfo lists, it may happen that the
    // freed memory is re-used for another window.
    FOR_ALL_BUFFERS(buf)
	FOR_ALL_BUF_WININFO(buf, wip)
	    if (wip->wi_win == wp)
	    {
		wininfo_T	*wip2;

		// If there already is an entry with "wi_win" set to NULL it
		// must be removed, it would never be used.
		// Skip "wip" itself, otherwise Coverity complains.
		FOR_ALL_BUF_WININFO(buf, wip2)
		    if (wip2 != wip && wip2->wi_win == NULL)
		    {
			if (wip2->wi_next != NULL)
			    wip2->wi_next->wi_prev = wip2->wi_prev;
			if (wip2->wi_prev == NULL)
			    buf->b_wininfo = wip2->wi_next;
			else
			    wip2->wi_prev->wi_next = wip2->wi_next;
			free_wininfo(wip2);
			break;
		    }

		wip->wi_win = NULL;
	    }

#ifdef FEAT_SEARCH_EXTRA
    clear_matches(wp);
#endif

    free_jumplist(wp);

#ifdef FEAT_QUICKFIX
    qf_free_all(wp);
#endif

#ifdef FEAT_GUI
    if (gui.in_use)
    {
	gui_mch_destroy_scrollbar(&wp->w_scrollbars[SBAR_LEFT]);
	gui_mch_destroy_scrollbar(&wp->w_scrollbars[SBAR_RIGHT]);
    }
#endif // FEAT_GUI

#ifdef FEAT_MENU
    remove_winbar(wp);
#endif
#ifdef FEAT_PROP_POPUP
    free_callback(&wp->w_close_cb);
    free_callback(&wp->w_filter_cb);
    for (i = 0; i < 4; ++i)
	VIM_CLEAR(wp->w_border_highlight[i]);
    vim_free(wp->w_scrollbar_highlight);
    vim_free(wp->w_thumb_highlight);
    vim_free(wp->w_popup_title);
    list_unref(wp->w_popup_mask);
    vim_free(wp->w_popup_mask_cells);
#endif

#ifdef FEAT_SYN_HL
    vim_free(wp->w_p_cc_cols);
#endif

    if (win_valid_any_tab(wp))
	win_remove(wp, tp);
    if (autocmd_busy)
    {
	wp->w_next = au_pending_free_win;
	au_pending_free_win = wp;
    }
    else
	vim_free(wp);

    unblock_autocmds();
}

/*
 * Return TRUE if "wp" is not in the list of windows: the autocmd window or a
 * popup window.
 */
    int
win_unlisted(win_T *wp)
{
    return is_aucmd_win(wp) || WIN_IS_POPUP(wp);
}

#if defined(FEAT_PROP_POPUP) || defined(PROTO)
/*
 * Free a popup window.  This does not take the window out of the window list
 * and assumes there is only one toplevel frame, no split.
 */
    void
win_free_popup(win_T *win)
{
    if (win->w_buffer != NULL)
    {
	if (bt_popup(win->w_buffer))
	    win_close_buffer(win, DOBUF_WIPE_REUSE, FALSE);
	else
	    close_buffer(win, win->w_buffer, 0, FALSE, FALSE);
    }
# if defined(FEAT_TIMERS)
    // the timer may have been cleared, making the pointer invalid
    if (timer_valid(win->w_popup_timer))
	stop_timer(win->w_popup_timer);
# endif
    vim_free(win->w_frame);
    win_free(win, NULL);
}
#endif

/*
 * Append window "wp" in the window list after window "after".
 */
    static void
win_append(win_T *after, win_T *wp)
{
    win_T	*before;

    if (after == NULL)	    // after NULL is in front of the first
	before = firstwin;
    else
	before = after->w_next;

    wp->w_next = before;
    wp->w_prev = after;
    if (after == NULL)
	firstwin = wp;
    else
	after->w_next = wp;
    if (before == NULL)
	lastwin = wp;
    else
	before->w_prev = wp;
}

/*
 * Remove a window from the window list.
 */
    void
win_remove(
    win_T	*wp,
    tabpage_T	*tp)		// tab page "win" is in, NULL for current
{
    if (wp->w_prev != NULL)
	wp->w_prev->w_next = wp->w_next;
    else if (tp == NULL)
	firstwin = curtab->tp_firstwin = wp->w_next;
    else
	tp->tp_firstwin = wp->w_next;

    if (wp->w_next != NULL)
	wp->w_next->w_prev = wp->w_prev;
    else if (tp == NULL)
	lastwin = curtab->tp_lastwin = wp->w_prev;
    else
	tp->tp_lastwin = wp->w_prev;
}

/*
 * Append frame "frp" in a frame list after frame "after".
 */
    static void
frame_append(frame_T *after, frame_T *frp)
{
    frp->fr_next = after->fr_next;
    after->fr_next = frp;
    if (frp->fr_next != NULL)
	frp->fr_next->fr_prev = frp;
    frp->fr_prev = after;
}

/*
 * Insert frame "frp" in a frame list before frame "before".
 */
    static void
frame_insert(frame_T *before, frame_T *frp)
{
    frp->fr_next = before;
    frp->fr_prev = before->fr_prev;
    before->fr_prev = frp;
    if (frp->fr_prev != NULL)
	frp->fr_prev->fr_next = frp;
    else
	frp->fr_parent->fr_child = frp;
}

/*
 * Remove a frame from a frame list.
 */
    static void
frame_remove(frame_T *frp)
{
    if (frp->fr_prev != NULL)
	frp->fr_prev->fr_next = frp->fr_next;
    else
	frp->fr_parent->fr_child = frp->fr_next;
    if (frp->fr_next != NULL)
	frp->fr_next->fr_prev = frp->fr_prev;
}

/*
 * Allocate w_lines[] for window "wp".
 * Return FAIL for failure, OK for success.
 */
    int
win_alloc_lines(win_T *wp)
{
    wp->w_lines_valid = 0;
    wp->w_lines = ALLOC_CLEAR_MULT(wline_T, Rows);
    if (wp->w_lines == NULL)
	return FAIL;
    return OK;
}

/*
 * free lsize arrays for a window
 */
    void
win_free_lsize(win_T *wp)
{
    // TODO: why would wp be NULL here?
    if (wp != NULL)
	VIM_CLEAR(wp->w_lines);
}

/*
 * Called from win_new_shellsize() after Rows changed.
 * This only does the current tab page, others must be done when made active.
 */
    void
shell_new_rows(void)
{
    int		h = (int)ROWS_AVAIL;

    if (firstwin == NULL)	// not initialized yet
	return;
    if (h < frame_minheight(topframe, NULL))
	h = frame_minheight(topframe, NULL);

    // First try setting the heights of windows with 'winfixheight'.  If
    // that doesn't result in the right height, forget about that option.
    frame_new_height(topframe, h, FALSE, TRUE);
    if (!frame_check_height(topframe, h))
	frame_new_height(topframe, h, FALSE, FALSE);

    (void)win_comp_pos();		// recompute w_winrow and w_wincol
    compute_cmdrow();
    curtab->tp_ch_used = p_ch;

    if (!skip_win_fix_scroll)
	win_fix_scroll(TRUE);

#if 0
    // Disabled: don't want making the screen smaller make a window larger.
    if (p_ea)
	win_equal(curwin, FALSE, 'v');
#endif
}

/*
 * Called from win_new_shellsize() after Columns changed.
 */
    void
shell_new_columns(void)
{
    if (firstwin == NULL)	// not initialized yet
	return;

    // First try setting the widths of windows with 'winfixwidth'.  If that
    // doesn't result in the right width, forget about that option.
    frame_new_width(topframe, (int)Columns, FALSE, TRUE);
    if (!frame_check_width(topframe, Columns))
	frame_new_width(topframe, (int)Columns, FALSE, FALSE);

    (void)win_comp_pos();		// recompute w_winrow and w_wincol
#if 0
    // Disabled: don't want making the screen smaller make a window larger.
    if (p_ea)
	win_equal(curwin, FALSE, 'h');
#endif
}

/*
 * Save the size of all windows in "gap".
 */
    void
win_size_save(garray_T *gap)
{
    win_T	*wp;

    ga_init2(gap, sizeof(int), 1);
    if (ga_grow(gap, win_count() * 2 + 1) == FAIL)
	return;

    // first entry is the total lines available for windows
    ((int *)gap->ga_data)[gap->ga_len++] = ROWS_AVAIL - last_stl_height(FALSE);

    FOR_ALL_WINDOWS(wp)
    {
	((int *)gap->ga_data)[gap->ga_len++] =
	    wp->w_width + wp->w_vsep_width;
	((int *)gap->ga_data)[gap->ga_len++] = wp->w_height;
    }
}

/*
 * Restore window sizes, but only if the number of windows is still the same
 * and total lines available for windows didn't change.
 * Does not free the growarray.
 */
    void
win_size_restore(garray_T *gap)
{
    win_T	*wp;
    int		i, j;

    if (win_count() * 2 + 1 == gap->ga_len
	    && ((int *)gap->ga_data)[0] == ROWS_AVAIL - last_stl_height(FALSE))
    {
	// The order matters, because frames contain other frames, but it's
	// difficult to get right. The easy way out is to do it twice.
	for (j = 0; j < 2; ++j)
	{
	    i = 1;
	    FOR_ALL_WINDOWS(wp)
	    {
		frame_setwidth(wp->w_frame, ((int *)gap->ga_data)[i++]);
		win_setheight_win(((int *)gap->ga_data)[i++], wp);
	    }
	}
	// recompute the window positions
	(void)win_comp_pos();
    }
}

/*
 * Update the position for all windows, using the width and height of the
 * frames.
 * Returns the row just after the last window.
 */
    int
win_comp_pos(void)
{
    int		row = tabline_height();
    int		col = 0;

    frame_comp_pos(topframe, &row, &col);
    return row;
}

/*
 * Update the position of the windows in frame "topfrp", using the width and
 * height of the frames.
 * "*row" and "*col" are the top-left position of the frame.  They are updated
 * to the bottom-right position plus one.
 */
    static void
frame_comp_pos(frame_T *topfrp, int *row, int *col)
{
    win_T	*wp;
    frame_T	*frp;
    int		startcol;
    int		startrow;
    int		h;

    wp = topfrp->fr_win;
    if (wp != NULL)
    {
	if (wp->w_winrow != *row || wp->w_wincol != *col)
	{
	    // position changed, redraw
	    wp->w_winrow = *row;
	    wp->w_wincol = *col;
	    redraw_win_later(wp, UPD_NOT_VALID);
	    wp->w_redr_status = TRUE;
	}
	// WinBar will not show if the window height is zero
	h = VISIBLE_HEIGHT(wp) + wp->w_status_height;
	*row += h > topfrp->fr_height ? topfrp->fr_height : h;
	*col += wp->w_width + wp->w_vsep_width;
    }
    else
    {
	startrow = *row;
	startcol = *col;
	FOR_ALL_FRAMES(frp, topfrp->fr_child)
	{
	    if (topfrp->fr_layout == FR_ROW)
		*row = startrow;	// all frames are at the same row
	    else
		*col = startcol;	// all frames are at the same col
	    frame_comp_pos(frp, row, col);
	}
    }
}

/*
 * Make the current window show at least one line and one column.
 */
    void
win_ensure_size(void)
{
    if (curwin->w_height == 0)
	win_setheight(1);
    if (curwin->w_width == 0)
	win_setwidth(1);
}

/*
 * Set current window height and take care of repositioning other windows to
 * fit around it.
 */
    void
win_setheight(int height)
{
    win_setheight_win(height, curwin);
}

/*
 * Set the window height of window "win" and take care of repositioning other
 * windows to fit around it.
 */
    void
win_setheight_win(int height, win_T *win)
{
    int		row;

    if (win == curwin)
    {
	// Always keep current window at least one line high, even when
	// 'winminheight' is zero.
	if (height < p_wmh)
	    height = p_wmh;
	if (height == 0)
	    height = 1;
	height += WINBAR_HEIGHT(curwin);
    }

    frame_setheight(win->w_frame, height + win->w_status_height);

    // recompute the window positions
    row = win_comp_pos();

    /*
     * If there is extra space created between the last window and the command
     * line, clear it.
     */
    if (full_screen && msg_scrolled == 0 && row < cmdline_row)
	screen_fill(row, cmdline_row, 0, (int)Columns, ' ', ' ', 0);
    cmdline_row = row;
    msg_row = row;
    msg_col = 0;

    win_fix_scroll(TRUE);

    redraw_all_later(UPD_NOT_VALID);
}

/*
 * Set the height of a frame to "height" and take care that all frames and
 * windows inside it are resized.  Also resize frames on the left and right if
 * the are in the same FR_ROW frame.
 *
 * Strategy:
 * If the frame is part of a FR_COL frame, try fitting the frame in that
 * frame.  If that doesn't work (the FR_COL frame is too small), recursively
 * go to containing frames to resize them and make room.
 * If the frame is part of a FR_ROW frame, all frames must be resized as well.
 * Check for the minimal height of the FR_ROW frame.
 * At the top level we can also use change the command line height.
 */
    static void
frame_setheight(frame_T *curfrp, int height)
{
    int		room;		// total number of lines available
    int		take;		// number of lines taken from other windows
    int		room_cmdline;	// lines available from cmdline
    int		run;
    frame_T	*frp;
    int		h;
    int		room_reserved;

    // If the height already is the desired value, nothing to do.
    if (curfrp->fr_height == height)
	return;

    if (curfrp->fr_parent == NULL)
    {
	// topframe: can only change the command line height
	if (height > ROWS_AVAIL)
	    height = ROWS_AVAIL;
	if (height > 0)
	    frame_new_height(curfrp, height, FALSE, FALSE);
    }
    else if (curfrp->fr_parent->fr_layout == FR_ROW)
    {
	// Row of frames: Also need to resize frames left and right of this
	// one.  First check for the minimal height of these.
	h = frame_minheight(curfrp->fr_parent, NULL);
	if (height < h)
	    height = h;
	frame_setheight(curfrp->fr_parent, height);
    }
    else
    {
	/*
	 * Column of frames: try to change only frames in this column.
	 */
	/*
	 * Do this twice:
	 * 1: compute room available, if it's not enough try resizing the
	 *    containing frame.
	 * 2: compute the room available and adjust the height to it.
	 * Try not to reduce the height of a window with 'winfixheight' set.
	 */
	for (run = 1; run <= 2; ++run)
	{
	    room = 0;
	    room_reserved = 0;
	    FOR_ALL_FRAMES(frp, curfrp->fr_parent->fr_child)
	    {
		if (frp != curfrp
			&& frp->fr_win != NULL
			&& frp->fr_win->w_p_wfh)
		    room_reserved += frp->fr_height;
		room += frp->fr_height;
		if (frp != curfrp)
		    room -= frame_minheight(frp, NULL);
	    }
	    if (curfrp->fr_width != Columns)
		room_cmdline = 0;
	    else
	    {
		room_cmdline = Rows - p_ch - (lastwin->w_winrow
						+ VISIBLE_HEIGHT(lastwin)
						+ lastwin->w_status_height);
		if (room_cmdline < 0)
		    room_cmdline = 0;
	    }

	    if (height <= room + room_cmdline)
		break;
	    if (run == 2 || curfrp->fr_width == Columns)
	    {
		height = room + room_cmdline;
		break;
	    }
	    frame_setheight(curfrp->fr_parent, height
		+ frame_minheight(curfrp->fr_parent, NOWIN) - (int)p_wmh - 1);
	}

	/*
	 * Compute the number of lines we will take from others frames (can be
	 * negative!).
	 */
	take = height - curfrp->fr_height;

	// If there is not enough room, also reduce the height of a window
	// with 'winfixheight' set.
	if (height > room + room_cmdline - room_reserved)
	    room_reserved = room + room_cmdline - height;
	// If there is only a 'winfixheight' window and making the
	// window smaller, need to make the other window taller.
	if (take < 0 && room - curfrp->fr_height < room_reserved)
	    room_reserved = 0;

	if (take > 0 && room_cmdline > 0)
	{
	    // use lines from cmdline first
	    if (take < room_cmdline)
		room_cmdline = take;
	    take -= room_cmdline;
	    topframe->fr_height += room_cmdline;
	}

	/*
	 * set the current frame to the new height
	 */
	frame_new_height(curfrp, height, FALSE, FALSE);

	/*
	 * First take lines from the frames after the current frame.  If
	 * that is not enough, takes lines from frames above the current
	 * frame.
	 */
	for (run = 0; run < 2; ++run)
	{
	    if (run == 0)
		frp = curfrp->fr_next;	// 1st run: start with next window
	    else
		frp = curfrp->fr_prev;	// 2nd run: start with prev window
	    while (frp != NULL && take != 0)
	    {
		h = frame_minheight(frp, NULL);
		if (room_reserved > 0
			&& frp->fr_win != NULL
			&& frp->fr_win->w_p_wfh)
		{
		    if (room_reserved >= frp->fr_height)
			room_reserved -= frp->fr_height;
		    else
		    {
			if (frp->fr_height - room_reserved > take)
			    room_reserved = frp->fr_height - take;
			take -= frp->fr_height - room_reserved;
			frame_new_height(frp, room_reserved, FALSE, FALSE);
			room_reserved = 0;
		    }
		}
		else
		{
		    if (frp->fr_height - take < h)
		    {
			take -= frp->fr_height - h;
			frame_new_height(frp, h, FALSE, FALSE);
		    }
		    else
		    {
			frame_new_height(frp, frp->fr_height - take,
								FALSE, FALSE);
			take = 0;
		    }
		}
		if (run == 0)
		    frp = frp->fr_next;
		else
		    frp = frp->fr_prev;
	    }
	}
    }
}

/*
 * Set current window width and take care of repositioning other windows to
 * fit around it.
 */
    void
win_setwidth(int width)
{
    win_setwidth_win(width, curwin);
}

    void
win_setwidth_win(int width, win_T *wp)
{
    // Always keep current window at least one column wide, even when
    // 'winminwidth' is zero.
    if (wp == curwin)
    {
	if (width < p_wmw)
	    width = p_wmw;
	if (width == 0)
	    width = 1;
    }
    else if (width < 0)
	width = 0;

    frame_setwidth(wp->w_frame, width + wp->w_vsep_width);

    // recompute the window positions
    (void)win_comp_pos();

    redraw_all_later(UPD_NOT_VALID);
}

/*
 * Set the width of a frame to "width" and take care that all frames and
 * windows inside it are resized.  Also resize frames above and below if the
 * are in the same FR_ROW frame.
 *
 * Strategy is similar to frame_setheight().
 */
    static void
frame_setwidth(frame_T *curfrp, int width)
{
    int		room;		// total number of lines available
    int		take;		// number of lines taken from other windows
    int		run;
    frame_T	*frp;
    int		w;
    int		room_reserved;

    // If the width already is the desired value, nothing to do.
    if (curfrp->fr_width == width)
	return;

    if (curfrp->fr_parent == NULL)
	// topframe: can't change width
	return;

    if (curfrp->fr_parent->fr_layout == FR_COL)
    {
	// Column of frames: Also need to resize frames above and below of
	// this one.  First check for the minimal width of these.
	w = frame_minwidth(curfrp->fr_parent, NULL);
	if (width < w)
	    width = w;
	frame_setwidth(curfrp->fr_parent, width);
    }
    else
    {
	/*
	 * Row of frames: try to change only frames in this row.
	 *
	 * Do this twice:
	 * 1: compute room available, if it's not enough try resizing the
	 *    containing frame.
	 * 2: compute the room available and adjust the width to it.
	 */
	for (run = 1; run <= 2; ++run)
	{
	    room = 0;
	    room_reserved = 0;
	    FOR_ALL_FRAMES(frp, curfrp->fr_parent->fr_child)
	    {
		if (frp != curfrp
			&& frp->fr_win != NULL
			&& frp->fr_win->w_p_wfw)
		    room_reserved += frp->fr_width;
		room += frp->fr_width;
		if (frp != curfrp)
		    room -= frame_minwidth(frp, NULL);
	    }

	    if (width <= room)
		break;
	    if (run == 2 || curfrp->fr_height >= ROWS_AVAIL)
	    {
		width = room;
		break;
	    }
	    frame_setwidth(curfrp->fr_parent, width
		 + frame_minwidth(curfrp->fr_parent, NOWIN) - (int)p_wmw - 1);
	}

	/*
	 * Compute the number of lines we will take from others frames (can be
	 * negative!).
	 */
	take = width - curfrp->fr_width;

	// If there is not enough room, also reduce the width of a window
	// with 'winfixwidth' set.
	if (width > room - room_reserved)
	    room_reserved = room - width;
	// If there is only a 'winfixwidth' window and making the
	// window smaller, need to make the other window narrower.
	if (take < 0 && room - curfrp->fr_width < room_reserved)
	    room_reserved = 0;

	/*
	 * set the current frame to the new width
	 */
	frame_new_width(curfrp, width, FALSE, FALSE);

	/*
	 * First take lines from the frames right of the current frame.  If
	 * that is not enough, takes lines from frames left of the current
	 * frame.
	 */
	for (run = 0; run < 2; ++run)
	{
	    if (run == 0)
		frp = curfrp->fr_next;	// 1st run: start with next window
	    else
		frp = curfrp->fr_prev;	// 2nd run: start with prev window
	    while (frp != NULL && take != 0)
	    {
		w = frame_minwidth(frp, NULL);
		if (room_reserved > 0
			&& frp->fr_win != NULL
			&& frp->fr_win->w_p_wfw)
		{
		    if (room_reserved >= frp->fr_width)
			room_reserved -= frp->fr_width;
		    else
		    {
			if (frp->fr_width - room_reserved > take)
			    room_reserved = frp->fr_width - take;
			take -= frp->fr_width - room_reserved;
			frame_new_width(frp, room_reserved, FALSE, FALSE);
			room_reserved = 0;
		    }
		}
		else
		{
		    if (frp->fr_width - take < w)
		    {
			take -= frp->fr_width - w;
			frame_new_width(frp, w, FALSE, FALSE);
		    }
		    else
		    {
			frame_new_width(frp, frp->fr_width - take,
								FALSE, FALSE);
			take = 0;
		    }
		}
		if (run == 0)
		    frp = frp->fr_next;
		else
		    frp = frp->fr_prev;
	    }
	}
    }
}

/*
 * Check 'winminheight' for a valid value and reduce it if needed.
 */
    void
win_setminheight(void)
{
    int		room;
    int		needed;
    int		first = TRUE;

    // loop until there is a 'winminheight' that is possible
    while (p_wmh > 0)
    {
	room = Rows - p_ch;
	needed = min_rows() - 1;  // 1 was added for the cmdline
	if (room >= needed)
	    break;
	--p_wmh;
	if (first)
	{
	    emsg(_(e_not_enough_room));
	    first = FALSE;
	}
    }
}

/*
 * Check 'winminwidth' for a valid value and reduce it if needed.
 */
    void
win_setminwidth(void)
{
    int		room;
    int		needed;
    int		first = TRUE;

    // loop until there is a 'winminheight' that is possible
    while (p_wmw > 0)
    {
	room = Columns;
	needed = frame_minwidth(topframe, NULL);
	if (room >= needed)
	    break;
	--p_wmw;
	if (first)
	{
	    emsg(_(e_not_enough_room));
	    first = FALSE;
	}
    }
}

/*
 * Status line of dragwin is dragged "offset" lines down (negative is up).
 */
    void
win_drag_status_line(win_T *dragwin, int offset)
{
    frame_T	*curfr;
    frame_T	*fr;
    int		room;
    int		row;
    int		up;	// if TRUE, drag status line up, otherwise down
    int		n;

    fr = dragwin->w_frame;
    curfr = fr;
    if (fr != topframe)		// more than one window
    {
	fr = fr->fr_parent;
	// When the parent frame is not a column of frames, its parent should
	// be.
	if (fr->fr_layout != FR_COL)
	{
	    curfr = fr;
	    if (fr != topframe)	// only a row of windows, may drag statusline
		fr = fr->fr_parent;
	}
    }

    // If this is the last frame in a column, may want to resize the parent
    // frame instead (go two up to skip a row of frames).
    while (curfr != topframe && curfr->fr_next == NULL)
    {
	if (fr != topframe)
	    fr = fr->fr_parent;
	curfr = fr;
	if (fr != topframe)
	    fr = fr->fr_parent;
    }

    if (offset < 0) // drag up
    {
	up = TRUE;
	offset = -offset;
	// sum up the room of the current frame and above it
	if (fr == curfr)
	{
	    // only one window
	    room = fr->fr_height - frame_minheight(fr, NULL);
	}
	else
	{
	    room = 0;
	    for (fr = fr->fr_child; ; fr = fr->fr_next)
	    {
		room += fr->fr_height - frame_minheight(fr, NULL);
		if (fr == curfr)
		    break;
	    }
	}
	fr = curfr->fr_next;		// put fr at frame that grows
    }
    else    // drag down
    {
	up = FALSE;
	/*
	 * Only dragging the last status line can reduce p_ch.
	 */
	room = Rows - cmdline_row;
	if (curfr->fr_next == NULL)
	    --room;
	else
	    room -= p_ch;
	if (room < 0)
	    room = 0;
	// sum up the room of frames below of the current one
	FOR_ALL_FRAMES(fr, curfr->fr_next)
	    room += fr->fr_height - frame_minheight(fr, NULL);
	fr = curfr;			// put fr at window that grows
    }

    if (room < offset)		// Not enough room
	offset = room;		// Move as far as we can
    if (offset <= 0)
	return;

    /*
     * Grow frame fr by "offset" lines.
     * Doesn't happen when dragging the last status line up.
     */
    if (fr != NULL)
	frame_new_height(fr, fr->fr_height + offset, up, FALSE);

    if (up)
	fr = curfr;		// current frame gets smaller
    else
	fr = curfr->fr_next;	// next frame gets smaller

    /*
     * Now make the other frames smaller.
     */
    while (fr != NULL && offset > 0)
    {
	n = frame_minheight(fr, NULL);
	if (fr->fr_height - offset <= n)
	{
	    offset -= fr->fr_height - n;
	    frame_new_height(fr, n, !up, FALSE);
	}
	else
	{
	    frame_new_height(fr, fr->fr_height - offset, !up, FALSE);
	    break;
	}
	if (up)
	    fr = fr->fr_prev;
	else
	    fr = fr->fr_next;
    }
    row = win_comp_pos();
    screen_fill(row, cmdline_row, 0, (int)Columns, ' ', ' ', 0);
    cmdline_row = row;
    p_ch = MAX(Rows - cmdline_row, 1);
    curtab->tp_ch_used = p_ch;

    win_fix_scroll(TRUE);

    redraw_all_later(UPD_SOME_VALID);
    showmode();
}

/*
 * Separator line of dragwin is dragged "offset" lines right (negative is left).
 */
    void
win_drag_vsep_line(win_T *dragwin, int offset)
{
    frame_T	*curfr;
    frame_T	*fr;
    int		room;
    int		left;	// if TRUE, drag separator line left, otherwise right
    int		n;

    fr = dragwin->w_frame;
    if (fr == topframe)		// only one window (cannot happen?)
	return;
    curfr = fr;
    fr = fr->fr_parent;
    // When the parent frame is not a row of frames, its parent should be.
    if (fr->fr_layout != FR_ROW)
    {
	if (fr == topframe)	// only a column of windows (cannot happen?)
	    return;
	curfr = fr;
	fr = fr->fr_parent;
    }

    // If this is the last frame in a row, may want to resize a parent
    // frame instead.
    while (curfr->fr_next == NULL)
    {
	if (fr == topframe)
	    break;
	curfr = fr;
	fr = fr->fr_parent;
	if (fr != topframe)
	{
	    curfr = fr;
	    fr = fr->fr_parent;
	}
    }

    if (offset < 0) // drag left
    {
	left = TRUE;
	offset = -offset;
	// sum up the room of the current frame and left of it
	room = 0;
	for (fr = fr->fr_child; ; fr = fr->fr_next)
	{
	    room += fr->fr_width - frame_minwidth(fr, NULL);
	    if (fr == curfr)
		break;
	}
	fr = curfr->fr_next;		// put fr at frame that grows
    }
    else    // drag right
    {
	left = FALSE;
	// sum up the room of frames right of the current one
	room = 0;
	FOR_ALL_FRAMES(fr, curfr->fr_next)
	    room += fr->fr_width - frame_minwidth(fr, NULL);
	fr = curfr;			// put fr at window that grows
    }

    if (room < offset)		// Not enough room
	offset = room;		// Move as far as we can
    if (offset <= 0)		// No room at all, quit.
	return;
    if (fr == NULL)
	// This can happen when calling win_move_separator() on the rightmost
	// window.  Just don't do anything.
	return;

    // grow frame fr by offset lines
    frame_new_width(fr, fr->fr_width + offset, left, FALSE);

    // shrink other frames: current and at the left or at the right
    if (left)
	fr = curfr;		// current frame gets smaller
    else
	fr = curfr->fr_next;	// next frame gets smaller

    while (fr != NULL && offset > 0)
    {
	n = frame_minwidth(fr, NULL);
	if (fr->fr_width - offset <= n)
	{
	    offset -= fr->fr_width - n;
	    frame_new_width(fr, n, !left, FALSE);
	}
	else
	{
	    frame_new_width(fr, fr->fr_width - offset, !left, FALSE);
	    break;
	}
	if (left)
	    fr = fr->fr_prev;
	else
	    fr = fr->fr_next;
    }
    (void)win_comp_pos();
    redraw_all_later(UPD_NOT_VALID);
}

#define FRACTION_MULT	16384L

/*
 * Set wp->w_fraction for the current w_wrow and w_height.
 * Has no effect when the window is less than two lines.
 */
    void
set_fraction(win_T *wp)
{
    if (wp->w_height > 1)
	// When cursor is in the first line the percentage is computed as if
	// it's halfway that line.  Thus with two lines it is 25%, with three
	// lines 17%, etc.  Similarly for the last line: 75%, 83%, etc.
	wp->w_fraction = ((long)wp->w_wrow * FRACTION_MULT
				     + FRACTION_MULT / 2) / (long)wp->w_height;
}

/*
 * Handle scroll position, depending on 'splitkeep'.  Replaces the
 * scroll_to_fraction() call from win_new_height() if 'splitkeep' is "screen"
 * or "topline".  Instead we iterate over all windows in a tabpage and
 * calculate the new scroll position.
 * TODO: Ensure this also works with wrapped lines.
 * Requires a not fully visible cursor line to be allowed at the bottom of
 * a window("zb"), probably only when 'smoothscroll' is also set.
 */
    static void
win_fix_scroll(int resize)
{
    if (*p_spk == 'c')
	return;  // 'splitkeep' is "cursor"

    skip_update_topline = TRUE;
    win_T	*wp;
    FOR_ALL_WINDOWS(wp)
    {
	// Skip when window height has not changed.
	if (wp->w_height != wp->w_prev_height)
	{
	    // Cursor position in this window may now be invalid.  It is kept
	    // potentially invalid until the window is made the current window.
	    wp->w_do_win_fix_cursor = TRUE;

	    // If window has moved update botline to keep the same screenlines.
	    if (*p_spk == 's' && wp->w_winrow != wp->w_prev_winrow
		      && wp->w_botline - 1 <= wp->w_buffer->b_ml.ml_line_count)
	    {
		int diff = (wp->w_winrow - wp->w_prev_winrow)
					  + (wp->w_height - wp->w_prev_height);
		linenr_T lnum = wp->w_cursor.lnum;
		wp->w_cursor.lnum = wp->w_botline - 1;

		//  Add difference in height and row to botline.
		if (diff > 0)
		    cursor_down_inner(wp, diff);
		else
		    cursor_up_inner(wp, -diff);

		// Scroll to put the new cursor position at the bottom of the
		// screen.
		wp->w_fraction = FRACTION_MULT;
		scroll_to_fraction(wp, wp->w_prev_height);

		wp->w_cursor.lnum = lnum;
	    }
	    else if (wp == curwin)
		wp->w_valid &= ~VALID_CROW;

	    invalidate_botline_win(wp);
	    validate_botline_win(wp);
	}
	wp->w_prev_height = wp->w_height;
	wp->w_prev_winrow = wp->w_winrow;
    }
    skip_update_topline = FALSE;
    // Ensure cursor is valid when not in normal mode or when resized.
    if (!(get_real_state() & (MODE_NORMAL|MODE_CMDLINE|MODE_TERMINAL)))
	win_fix_cursor(FALSE);
    else if (resize)
	win_fix_cursor(TRUE);
}

/*
 * Make sure the cursor position is valid for 'splitkeep'.
 * If it is not, put the cursor position in the jumplist and move it.
 * If we are not in normal mode ("normal" is FALSE), make it valid by scrolling
 * instead.
 */
    static void
win_fix_cursor(int normal)
{
    win_T	*wp = curwin;

    if (skip_win_fix_cursor
	    || !wp->w_do_win_fix_cursor
	    || wp->w_buffer->b_ml.ml_line_count < wp->w_height)
	return;

    wp->w_do_win_fix_cursor = FALSE;
    // Determine valid cursor range.
    long so = MIN(wp->w_height / 2, get_scrolloff_value());
    linenr_T lnum = wp->w_cursor.lnum;

    wp->w_cursor.lnum = wp->w_topline;
    cursor_down_inner(wp, so);
    linenr_T top = wp->w_cursor.lnum;

    wp->w_cursor.lnum = wp->w_botline - 1;
    cursor_up_inner(wp, so);
    linenr_T bot = wp->w_cursor.lnum;

    wp->w_cursor.lnum = lnum;

    // Check if cursor position is above or below valid cursor range.
    linenr_T nlnum = 0;
    if (lnum > bot && (wp->w_botline - wp->w_buffer->b_ml.ml_line_count) != 1)
	nlnum = bot;
    else if (lnum < top && wp->w_topline != 1)
	nlnum = (so == wp->w_height / 2) ? bot : top;

    if (nlnum != 0)  // Cursor is invalid for current scroll position.
    {
	if (normal)  // Save to jumplist and set cursor to avoid scrolling.
	{
	    setmark('\'');
	    wp->w_cursor.lnum = nlnum;
	}
	else  // Scroll instead when not in normal mode.
	{
	    wp->w_fraction = (nlnum == bot) ? FRACTION_MULT : 0;
	    scroll_to_fraction(wp, wp->w_prev_height);
	    validate_botline();
	}
    }
}

/*
 * Set the height of a window.
 * "height" excludes any window toolbar.
 * This takes care of the things inside the window, not what happens to the
 * window position, the frame or to other windows.
 */
    void
win_new_height(win_T *wp, int height)
{
    int		prev_height = wp->w_height;

    // Don't want a negative height.  Happens when splitting a tiny window.
    // Will equalize heights soon to fix it.
    if (height < 0)
	height = 0;
    if (wp->w_height == height)
	return;	    // nothing to do

    if (wp->w_height > 0)
    {
	if (wp == curwin && *p_spk == 'c')
	    // w_wrow needs to be valid. When setting 'laststatus' this may
	    // call win_new_height() recursively.
	    validate_cursor();
	if (wp->w_height != prev_height)
	    return;  // Recursive call already changed the size, bail out here
		     //	to avoid the following to mess things up.
	if (wp->w_wrow != wp->w_prev_fraction_row)
	    set_fraction(wp);
    }

    wp->w_height = height;
    wp->w_redr_status = TRUE;
    win_comp_scroll(wp);

    // There is no point in adjusting the scroll position when exiting.  Some
    // values might be invalid.
    if (!exiting && *p_spk == 'c')
    {
	wp->w_skipcol = 0;
	scroll_to_fraction(wp, prev_height);
    }
}

    void
scroll_to_fraction(win_T *wp, int prev_height)
{
    linenr_T	lnum;
    int		sline, line_size;
    int		height = wp->w_height;

    // Don't change w_topline in any of these cases:
    // - window height is 0
    // - 'scrollbind' is set and this isn't the current window
    // - window height is sufficient to display the whole buffer and first line
    //   is visible.
    if (height > 0
	   && (!wp->w_p_scb || wp == curwin)
	   && (height < wp->w_buffer->b_ml.ml_line_count || wp->w_topline > 1))
    {
	/*
	 * Find a value for w_topline that shows the cursor at the same
	 * relative position in the window as before (more or less).
	 */
	lnum = wp->w_cursor.lnum;
	if (lnum < 1)		// can happen when starting up
	    lnum = 1;
	wp->w_wrow = ((long)wp->w_fraction * (long)height - 1L)
							       / FRACTION_MULT;
	line_size = plines_win_col(wp, lnum, (long)(wp->w_cursor.col)) - 1;
	sline = wp->w_wrow - line_size;

	if (sline >= 0)
	{
	    // Make sure the whole cursor line is visible, if possible.
	    int rows = plines_win(wp, lnum, FALSE);

	    if (sline > wp->w_height - rows)
	    {
		sline = wp->w_height - rows;
		wp->w_wrow -= rows - line_size;
	    }
	}

	if (sline < 0)
	{
	    /*
	     * Cursor line would go off top of screen if w_wrow was this high.
	     * Make cursor line the first line in the window.  If not enough
	     * room use w_skipcol;
	     */
	    wp->w_wrow = line_size;
	    if (wp->w_wrow >= wp->w_height
				       && (wp->w_width - win_col_off(wp)) > 0)
	    {
		wp->w_skipcol += wp->w_width - win_col_off(wp);
		--wp->w_wrow;
		while (wp->w_wrow >= wp->w_height)
		{
		    wp->w_skipcol += wp->w_width - win_col_off(wp)
							   + win_col_off2(wp);
		    --wp->w_wrow;
		}
	    }
	}
	else if (sline > 0)
	{
	    while (sline > 0 && lnum > 1)
	    {
#ifdef FEAT_FOLDING
		hasFoldingWin(wp, lnum, &lnum, NULL, TRUE, NULL);
		if (lnum == 1)
		{
		    // first line in buffer is folded
		    line_size = 1;
		    --sline;
		    break;
		}
#endif
		--lnum;
#ifdef FEAT_DIFF
		if (lnum == wp->w_topline)
		    line_size = plines_win_nofill(wp, lnum, TRUE)
							      + wp->w_topfill;
		else
#endif
		    line_size = plines_win(wp, lnum, TRUE);
		sline -= line_size;
	    }

	    if (sline < 0)
	    {
		/*
		 * Line we want at top would go off top of screen.  Use next
		 * line instead.
		 */
#ifdef FEAT_FOLDING
		hasFoldingWin(wp, lnum, NULL, &lnum, TRUE, NULL);
#endif
		lnum++;
		wp->w_wrow -= line_size + sline;
	    }
	    else if (sline > 0)
	    {
		// First line of file reached, use that as topline.
		lnum = 1;
		wp->w_wrow -= sline;
	    }
	}
	set_topline(wp, lnum);
    }

    if (wp == curwin)
	curs_columns(FALSE);	// validate w_wrow

    if (prev_height > 0)
	wp->w_prev_fraction_row = wp->w_wrow;

    redraw_win_later(wp, UPD_SOME_VALID);
    invalidate_botline_win(wp);
}

/*
 * Set the width of a window.
 */
    void
win_new_width(win_T *wp, int width)
{
    // Should we give an error if width < 0?
    wp->w_width = width < 0 ? 0 : width;
    wp->w_lines_valid = 0;
    changed_line_abv_curs_win(wp);
    invalidate_botline_win(wp);

    if (wp == curwin && *p_spk == 'c')
	curs_columns(TRUE);	// validate w_wrow

    redraw_win_later(wp, UPD_NOT_VALID);
    wp->w_redr_status = TRUE;
}

    void
win_comp_scroll(win_T *wp)
{
#if defined(FEAT_EVAL)
    int old_w_p_scr = wp->w_p_scr;
#endif

    wp->w_p_scr = ((unsigned)wp->w_height >> 1);
    if (wp->w_p_scr == 0)
	wp->w_p_scr = 1;
#if defined(FEAT_EVAL)
    if (wp->w_p_scr != old_w_p_scr)
    {
	// Used by "verbose set scroll".
	wp->w_p_script_ctx[WV_SCROLL].sc_sid = SID_WINLAYOUT;
	wp->w_p_script_ctx[WV_SCROLL].sc_lnum = 0;
    }
#endif
}

/*
 * Command_height: called whenever p_ch has been changed.
 */
    void
command_height(void)
{
    int		h;
    frame_T	*frp;
    int		old_p_ch = curtab->tp_ch_used;

    // Use the value of p_ch that we remembered.  This is needed for when the
    // GUI starts up, we can't be sure in what order things happen.  And when
    // p_ch was changed in another tab page.
    curtab->tp_ch_used = p_ch;

    // If the space for the command line is already more than 'cmdheight' there
    // is nothing to do (window size must have decreased).
    if (p_ch > old_p_ch && cmdline_row <= Rows - p_ch)
	return;

    // Update cmdline_row to what it should be: just below the last window.
    cmdline_row = topframe->fr_height + tabline_height();

    // If cmdline_row is smaller than what it is supposed to be for 'cmdheight'
    // then set old_p_ch to what it would be, so that the windows get resized
    // properly for the new value.
    if (cmdline_row < Rows - p_ch)
	old_p_ch = Rows - cmdline_row;

    // Find bottom frame with width of screen.
    frp = lastwin->w_frame;
    while (frp->fr_width != Columns && frp->fr_parent != NULL)
	frp = frp->fr_parent;

    // Avoid changing the height of a window with 'winfixheight' set.
    while (frp->fr_prev != NULL && frp->fr_layout == FR_LEAF
						      && frp->fr_win->w_p_wfh)
	frp = frp->fr_prev;

    if (starting != NO_SCREEN)
    {
	cmdline_row = Rows - p_ch;

	if (p_ch > old_p_ch)		    // p_ch got bigger
	{
	    while (p_ch > old_p_ch)
	    {
		if (frp == NULL)
		{
		    emsg(_(e_not_enough_room));
		    p_ch = old_p_ch;
		    curtab->tp_ch_used = p_ch;
		    cmdline_row = Rows - p_ch;
		    break;
		}
		h = frp->fr_height - frame_minheight(frp, NULL);
		if (h > p_ch - old_p_ch)
		    h = p_ch - old_p_ch;
		old_p_ch += h;
		frame_add_height(frp, -h);
		frp = frp->fr_prev;
	    }

	    // Recompute window positions.
	    (void)win_comp_pos();

	    // clear the lines added to cmdline
	    if (full_screen)
		screen_fill(cmdline_row, (int)Rows, 0,
						   (int)Columns, ' ', ' ', 0);
	    msg_row = cmdline_row;
	    redraw_cmdline = TRUE;
	    return;
	}

	if (msg_row < cmdline_row)
	    msg_row = cmdline_row;
	redraw_cmdline = TRUE;
    }
    frame_add_height(frp, (int)(old_p_ch - p_ch));

    // Recompute window positions.
    if (frp != lastwin->w_frame)
	(void)win_comp_pos();
}

/*
 * Resize frame "frp" to be "n" lines higher (negative for less high).
 * Also resize the frames it is contained in.
 */
    static void
frame_add_height(frame_T *frp, int n)
{
    frame_new_height(frp, frp->fr_height + n, FALSE, FALSE);
    for (;;)
    {
	frp = frp->fr_parent;
	if (frp == NULL)
	    break;
	frp->fr_height += n;
    }
}

/*
 * Add or remove a status line for the bottom window(s), according to the
 * value of 'laststatus'.
 */
    void
last_status(
    int		morewin)	// pretend there are two or more windows
{
    // Don't make a difference between horizontal or vertical split.
    last_status_rec(topframe, last_stl_height(morewin) > 0);
}

    static void
last_status_rec(frame_T *fr, int statusline)
{
    frame_T	*fp;
    win_T	*wp;

    if (fr->fr_layout == FR_LEAF)
    {
	wp = fr->fr_win;
	if (wp->w_status_height != 0 && !statusline)
	{
	    // remove status line
	    win_new_height(wp, wp->w_height + 1);
	    wp->w_status_height = 0;
	    comp_col();
	}
	else if (wp->w_status_height == 0 && statusline)
	{
	    // Find a frame to take a line from.
	    fp = fr;
	    while (fp->fr_height <= frame_minheight(fp, NULL))
	    {
		if (fp == topframe)
		{
		    emsg(_(e_not_enough_room));
		    return;
		}
		// In a column of frames: go to frame above.  If already at
		// the top or in a row of frames: go to parent.
		if (fp->fr_parent->fr_layout == FR_COL && fp->fr_prev != NULL)
		    fp = fp->fr_prev;
		else
		    fp = fp->fr_parent;
	    }
	    wp->w_status_height = 1;
	    if (fp != fr)
	    {
		frame_new_height(fp, fp->fr_height - 1, FALSE, FALSE);
		frame_fix_height(wp);
		(void)win_comp_pos();
	    }
	    else
		win_new_height(wp, wp->w_height - 1);
	    comp_col();
	    redraw_all_later(UPD_SOME_VALID);
	}
	// Set prev_height when difference is due to 'laststatus'.
	if (abs(wp->w_height - wp->w_prev_height) == 1)
	    wp->w_prev_height = wp->w_height;
    }
    else if (fr->fr_layout == FR_ROW)
    {
	// vertically split windows, set status line for each one
	FOR_ALL_FRAMES(fp, fr->fr_child)
	    last_status_rec(fp, statusline);
    }
    else
    {
	// horizontally split window, set status line for last one
	for (fp = fr->fr_child; fp->fr_next != NULL; fp = fp->fr_next)
	    ;
	last_status_rec(fp, statusline);
    }
}

/*
 * Return the number of lines used by the tab page line.
 */
    int
tabline_height(void)
{
#ifdef FEAT_GUI_TABLINE
    // When the GUI has the tabline then this always returns zero.
    if (gui_use_tabline())
	return 0;
#endif
    switch (p_stal)
    {
	case 0: return 0;
	case 1: return (first_tabpage->tp_next == NULL) ? 0 : 1;
    }
    return 1;
}

/*
 * Return the height of the last window's statusline.
 */
    int
last_stl_height(
    int		morewin)	// pretend there are two or more windows
{
    return (p_ls == 2 || (p_ls == 1 && (morewin || !ONE_WINDOW)))
		? STATUS_HEIGHT : 0;
}

/*
 * Return the minimal number of rows that is needed on the screen to display
 * the current number of windows.
 */
    int
min_rows(void)
{
    int		total;
    tabpage_T	*tp;
    int		n;

    if (firstwin == NULL)	// not initialized yet
	return MIN_LINES;

    total = 0;
    FOR_ALL_TABPAGES(tp)
    {
	n = frame_minheight(tp->tp_topframe, NULL);
	if (total < n)
	    total = n;
    }
    total += tabline_height();
    total += 1;		// count the room for the command line
    return total;
}

/*
 * Return TRUE if there is only one window and only one tab page, not
 * counting a help or preview window, unless it is the current window.
 * Does not count unlisted windows.
 */
    int
only_one_window(void)
{
    int		count = 0;
    win_T	*wp;

#if defined(FEAT_PROP_POPUP)
    // If the current window is a popup then there always is another window.
    if (popup_is_popup(curwin))
	return FALSE;
#endif

    // If there is another tab page there always is another window.
    if (first_tabpage->tp_next != NULL)
	return FALSE;

    FOR_ALL_WINDOWS(wp)
	if (wp->w_buffer != NULL
		&& (!((bt_help(wp->w_buffer) && !bt_help(curbuf))
# ifdef FEAT_QUICKFIX
		    || wp->w_p_pvw
# endif
	     ) || wp == curwin) && !is_aucmd_win(wp))
	    ++count;
    return (count <= 1);
}

/*
 * Implementation of check_lnums() and check_lnums_nested().
 */
    static void
check_lnums_both(int do_curwin, int nested)
{
    win_T	*wp;
    tabpage_T	*tp;

    FOR_ALL_TAB_WINDOWS(tp, wp)
	if ((do_curwin || wp != curwin) && wp->w_buffer == curbuf)
	{
	    int need_adjust;

	    if (!nested)
	    {
		// save the original cursor position and topline
		wp->w_save_cursor.w_cursor_save = wp->w_cursor;
		wp->w_save_cursor.w_topline_save = wp->w_topline;
	    }

	    need_adjust = wp->w_cursor.lnum > curbuf->b_ml.ml_line_count;
	    if (need_adjust)
		wp->w_cursor.lnum = curbuf->b_ml.ml_line_count;
	    if (need_adjust || !nested)
		// save the (corrected) cursor position
		wp->w_save_cursor.w_cursor_corr = wp->w_cursor;

	    need_adjust = wp->w_topline > curbuf->b_ml.ml_line_count;
	    if (need_adjust)
		wp->w_topline = curbuf->b_ml.ml_line_count;
	    if (need_adjust || !nested)
		// save the (corrected) topline
		wp->w_save_cursor.w_topline_corr = wp->w_topline;
	}
}

/*
 * Correct the cursor line number in other windows.  Used after changing the
 * current buffer, and before applying autocommands.
 * When "do_curwin" is TRUE, also check current window.
 */
    void
check_lnums(int do_curwin)
{
    check_lnums_both(do_curwin, FALSE);
}

/*
 * Like check_lnums() but for when check_lnums() was already called.
 */
    void
check_lnums_nested(int do_curwin)
{
    check_lnums_both(do_curwin, TRUE);
}

/*
 * Reset cursor and topline to its stored values from check_lnums().
 * check_lnums() must have been called first!
 */
    void
reset_lnums(void)
{
    win_T	*wp;
    tabpage_T	*tp;

    FOR_ALL_TAB_WINDOWS(tp, wp)
	if (wp->w_buffer == curbuf)
	{
	    // Restore the value if the autocommand didn't change it and it was
	    // set.
	    if (EQUAL_POS(wp->w_save_cursor.w_cursor_corr, wp->w_cursor)
				  && wp->w_save_cursor.w_cursor_save.lnum != 0)
		wp->w_cursor = wp->w_save_cursor.w_cursor_save;
	    if (wp->w_save_cursor.w_topline_corr == wp->w_topline
				      && wp->w_save_cursor.w_topline_save != 0)
		wp->w_topline = wp->w_save_cursor.w_topline_save;
	}
}

/*
 * A snapshot of the window sizes, to restore them after closing the help
 * or other window.
 * Only these fields are used:
 * fr_layout
 * fr_width
 * fr_height
 * fr_next
 * fr_child
 * fr_win (only valid for the old curwin, NULL otherwise)
 */

/*
 * Create a snapshot of the current frame sizes.
 * "idx" is SNAP_HELP_IDX or SNAP_AUCMD_IDX.
 */
    void
make_snapshot(int idx)
{
    clear_snapshot(curtab, idx);
    make_snapshot_rec(topframe, &curtab->tp_snapshot[idx]);
}

    static void
make_snapshot_rec(frame_T *fr, frame_T **frp)
{
    *frp = ALLOC_CLEAR_ONE(frame_T);
    if (*frp == NULL)
	return;
    (*frp)->fr_layout = fr->fr_layout;
    (*frp)->fr_width = fr->fr_width;
    (*frp)->fr_height = fr->fr_height;
    if (fr->fr_next != NULL)
	make_snapshot_rec(fr->fr_next, &((*frp)->fr_next));
    if (fr->fr_child != NULL)
	make_snapshot_rec(fr->fr_child, &((*frp)->fr_child));
    if (fr->fr_layout == FR_LEAF && fr->fr_win == curwin)
	(*frp)->fr_win = curwin;
}

/*
 * Remove any existing snapshot.
 */
    static void
clear_snapshot(tabpage_T *tp, int idx)
{
    clear_snapshot_rec(tp->tp_snapshot[idx]);
    tp->tp_snapshot[idx] = NULL;
}

    static void
clear_snapshot_rec(frame_T *fr)
{
    if (fr == NULL)
	return;
    clear_snapshot_rec(fr->fr_next);
    clear_snapshot_rec(fr->fr_child);
    vim_free(fr);
}

/*
 * Traverse a snapshot to find the previous curwin.
 */
    static win_T *
get_snapshot_curwin_rec(frame_T *ft)
{
    win_T	*wp;

    if (ft->fr_next != NULL)
    {
	if ((wp = get_snapshot_curwin_rec(ft->fr_next)) != NULL)
	    return wp;
    }
    if (ft->fr_child != NULL)
    {
	if ((wp = get_snapshot_curwin_rec(ft->fr_child)) != NULL)
	    return wp;
    }

    return ft->fr_win;
}

/*
 * Return the current window stored in the snapshot or NULL.
 */
    static win_T *
get_snapshot_curwin(int idx)
{
    if (curtab->tp_snapshot[idx] == NULL)
	return NULL;

    return get_snapshot_curwin_rec(curtab->tp_snapshot[idx]);
}

/*
 * Restore a previously created snapshot, if there is any.
 * This is only done if the screen size didn't change and the window layout is
 * still the same.
 * "idx" is SNAP_HELP_IDX or SNAP_AUCMD_IDX.
 */
    void
restore_snapshot(
    int		idx,
    int		close_curwin)	    // closing current window
{
    win_T	*wp;

    if (curtab->tp_snapshot[idx] != NULL
	    && curtab->tp_snapshot[idx]->fr_width == topframe->fr_width
	    && curtab->tp_snapshot[idx]->fr_height == topframe->fr_height
	    && check_snapshot_rec(curtab->tp_snapshot[idx], topframe) == OK)
    {
	wp = restore_snapshot_rec(curtab->tp_snapshot[idx], topframe);
	win_comp_pos();
	if (wp != NULL && close_curwin)
	    win_goto(wp);
	redraw_all_later(UPD_NOT_VALID);
    }
    clear_snapshot(curtab, idx);
}

/*
 * Check if frames "sn" and "fr" have the same layout, same following frames
 * and same children.  And the window pointer is valid.
 */
    static int
check_snapshot_rec(frame_T *sn, frame_T *fr)
{
    if (sn->fr_layout != fr->fr_layout
	    || (sn->fr_next == NULL) != (fr->fr_next == NULL)
	    || (sn->fr_child == NULL) != (fr->fr_child == NULL)
	    || (sn->fr_next != NULL
		&& check_snapshot_rec(sn->fr_next, fr->fr_next) == FAIL)
	    || (sn->fr_child != NULL
		&& check_snapshot_rec(sn->fr_child, fr->fr_child) == FAIL)
	    || (sn->fr_win != NULL && !win_valid(sn->fr_win)))
	return FAIL;
    return OK;
}

/*
 * Copy the size of snapshot frame "sn" to frame "fr".  Do the same for all
 * following frames and children.
 * Returns a pointer to the old current window, or NULL.
 */
    static win_T *
restore_snapshot_rec(frame_T *sn, frame_T *fr)
{
    win_T	*wp = NULL;
    win_T	*wp2;

    fr->fr_height = sn->fr_height;
    fr->fr_width = sn->fr_width;
    if (fr->fr_layout == FR_LEAF)
    {
	frame_new_height(fr, fr->fr_height, FALSE, FALSE);
	frame_new_width(fr, fr->fr_width, FALSE, FALSE);
	wp = sn->fr_win;
    }
    if (sn->fr_next != NULL)
    {
	wp2 = restore_snapshot_rec(sn->fr_next, fr->fr_next);
	if (wp2 != NULL)
	    wp = wp2;
    }
    if (sn->fr_child != NULL)
    {
	wp2 = restore_snapshot_rec(sn->fr_child, fr->fr_child);
	if (wp2 != NULL)
	    wp = wp2;
    }
    return wp;
}

#if defined(FEAT_GUI) || defined(PROTO)
/*
 * Return TRUE if there is any vertically split window.
 */
    int
win_hasvertsplit(void)
{
    frame_T	*fr;

    if (topframe->fr_layout == FR_ROW)
	return TRUE;

    if (topframe->fr_layout == FR_COL)
	FOR_ALL_FRAMES(fr, topframe->fr_child)
	    if (fr->fr_layout == FR_ROW)
		return TRUE;

    return FALSE;
}
#endif

#if defined(FEAT_PYTHON) || defined(FEAT_PYTHON3) || defined(PROTO)
    int
get_win_number(win_T *wp, win_T *first_win)
{
    int		i = 1;
    win_T	*w;

    for (w = first_win; w != NULL && w != wp; w = W_NEXT(w))
	++i;

    if (w == NULL)
	return 0;
    else
	return i;
}

    int
get_tab_number(tabpage_T *tp UNUSED)
{
    int		i = 1;
    tabpage_T	*t;

    for (t = first_tabpage; t != NULL && t != tp; t = t->tp_next)
	++i;

    if (t == NULL)
	return 0;
    else
	return i;
}
#endif

/*
 * Return TRUE if "topfrp" and its children are at the right height.
 */
    static int
frame_check_height(frame_T *topfrp, int height)
{
    frame_T *frp;

    if (topfrp->fr_height != height)
	return FALSE;

    if (topfrp->fr_layout == FR_ROW)
	FOR_ALL_FRAMES(frp, topfrp->fr_child)
	    if (frp->fr_height != height)
		return FALSE;

    return TRUE;
}

/*
 * Return TRUE if "topfrp" and its children are at the right width.
 */
    static int
frame_check_width(frame_T *topfrp, int width)
{
    frame_T *frp;

    if (topfrp->fr_width != width)
	return FALSE;

    if (topfrp->fr_layout == FR_COL)
	FOR_ALL_FRAMES(frp, topfrp->fr_child)
	    if (frp->fr_width != width)
		return FALSE;

    return TRUE;
}

#if defined(FEAT_SYN_HL) || defined(PROTO)
/*
 * Simple int comparison function for use with qsort()
 */
    static int
int_cmp(const void *a, const void *b)
{
    return *(const int *)a - *(const int *)b;
}

/*
 * Handle setting 'colorcolumn' or 'textwidth' in window "wp".
 * Returns error message, NULL if it's OK.
 */
    char *
check_colorcolumn(win_T *wp)
{
    char_u	*s;
    int		col;
    int		count = 0;
    int		color_cols[256];
    int		i;
    int		j = 0;

    if (wp->w_buffer == NULL)
	return NULL;  // buffer was closed

    for (s = wp->w_p_cc; *s != NUL && count < 255;)
    {
	if (*s == '-' || *s == '+')
	{
	    // -N and +N: add to 'textwidth'
	    col = (*s == '-') ? -1 : 1;
	    ++s;
	    if (!VIM_ISDIGIT(*s))
		return e_invalid_argument;
	    col = col * getdigits(&s);
	    if (wp->w_buffer->b_p_tw == 0)
		goto skip;  // 'textwidth' not set, skip this item
	    col += wp->w_buffer->b_p_tw;
	    if (col < 0)
		goto skip;
	}
	else if (VIM_ISDIGIT(*s))
	    col = getdigits(&s);
	else
	    return e_invalid_argument;
	color_cols[count++] = col - 1;  // 1-based to 0-based
skip:
	if (*s == NUL)
	    break;
	if (*s != ',')
	    return e_invalid_argument;
	if (*++s == NUL)
	    return e_invalid_argument;  // illegal trailing comma as in "set cc=80,"
    }

    vim_free(wp->w_p_cc_cols);
    if (count == 0)
	wp->w_p_cc_cols = NULL;
    else
    {
	wp->w_p_cc_cols = ALLOC_MULT(int, count + 1);
	if (wp->w_p_cc_cols != NULL)
	{
	    // sort the columns for faster usage on screen redraw inside
	    // win_line()
	    qsort(color_cols, count, sizeof(int), int_cmp);

	    for (i = 0; i < count; ++i)
		// skip duplicates
		if (j == 0 || wp->w_p_cc_cols[j - 1] != color_cols[i])
		    wp->w_p_cc_cols[j++] = color_cols[i];
	    wp->w_p_cc_cols[j] = -1;  // end marker
	}
    }

    return NULL;  // no error
}
#endif